Imported QtWebKit TP3 (git b57bc6801f1876c3220d5a4bfea33d620d477443)

Change-Id: I3b1d8a2808782c9f34d50240000e20cb38d3680f
Reviewed-by: Konstantin Tokarev <annulen@yandex.ru>

1 files changed, 4630 insertions, 3377 deletions

diff --git a/Source/WebCore/css/CSSParser.cpp b/Source/WebCore/css/CSSParser.cpp
index 54fd5e238..9aec1c8ac 100644
--- a/Source/WebCore/css/CSSParser.cpp
+++ b/Source/WebCore/css/CSSParser.cpp
@@ -1,12 +1,13 @@
 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
- * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2004-2015 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
- * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
+ * Copyright (C) 2012, 2013 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
+ * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ -27,88 +28,97 @@
 #include "config.h"
 #include "CSSParser.h"
 
+#include "CSSAnimationTriggerScrollValue.h"
 #include "CSSAspectRatioValue.h"
 #include "CSSBasicShapes.h"
 #include "CSSBorderImage.h"
 #include "CSSCanvasValue.h"
+#include "CSSContentDistributionValue.h"
 #include "CSSCrossfadeValue.h"
 #include "CSSCursorImageValue.h"
+#include "CSSCustomPropertyValue.h"
+#include "CSSFilterImageValue.h"
 #include "CSSFontFaceRule.h"
 #include "CSSFontFaceSrcValue.h"
+#include "CSSFontFeatureValue.h"
+#include "CSSFontValue.h"
 #include "CSSFunctionValue.h"
 #include "CSSGradientValue.h"
 #include "CSSImageValue.h"
 #include "CSSInheritedValue.h"
 #include "CSSInitialValue.h"
+#include "CSSKeyframeRule.h"
+#include "CSSKeyframesRule.h"
 #include "CSSLineBoxContainValue.h"
 #include "CSSMediaRule.h"
+#include "CSSNamedImageValue.h"
 #include "CSSPageRule.h"
 #include "CSSPrimitiveValue.h"
+#include "CSSPrimitiveValueMappings.h"
 #include "CSSPropertySourceData.h"
 #include "CSSReflectValue.h"
+#include "CSSRevertValue.h"
 #include "CSSSelector.h"
+#include "CSSShadowValue.h"
 #include "CSSStyleSheet.h"
 #include "CSSTimingFunctionValue.h"
 #include "CSSUnicodeRangeValue.h"
+#include "CSSUnsetValue.h"
 #include "CSSValueKeywords.h"
 #include "CSSValueList.h"
 #include "CSSValuePool.h"
-#if ENABLE(CSS_VARIABLES)
-#include "CSSVariableValue.h"
-#endif
+#include "CSSVariableDependentValue.h"
 #include "Counter.h"
 #include "Document.h"
 #include "FloatConversion.h"
-#include "FontFeatureValue.h"
-#include "FontValue.h"
+#include "GridCoordinate.h"
 #include "HTMLParserIdioms.h"
 #include "HashTools.h"
-#include "HistogramSupport.h"
 #include "MediaList.h"
 #include "MediaQueryExp.h"
 #include "Page.h"
-#include "PageConsole.h"
+#include "PageConsoleClient.h"
 #include "Pair.h"
 #include "Rect.h"
 #include "RenderTheme.h"
 #include "RuntimeEnabledFeatures.h"
 #include "SVGParserUtilities.h"
+#include "SVGPathByteStream.h"
+#include "SVGPathUtilities.h"
+#include "SelectorChecker.h"
+#include "SelectorCheckerTestFunctions.h"
 #include "Settings.h"
-#include "ShadowValue.h"
-#include "StylePropertySet.h"
+#include "StyleProperties.h"
 #include "StylePropertyShorthand.h"
 #include "StyleRule.h"
 #include "StyleRuleImport.h"
 #include "StyleSheetContents.h"
 #include "TextEncoding.h"
-#include "WebKitCSSKeyframeRule.h"
-#include "WebKitCSSKeyframesRule.h"
+#include "WebKitCSSFilterValue.h"
 #include "WebKitCSSRegionRule.h"
 #include "WebKitCSSTransformValue.h"
+#include <JavaScriptCore/Profile.h>
+#include <bitset>
 #include <limits.h>
-#include <wtf/BitArray.h>
 #include <wtf/HexNumber.h>
+#include <wtf/NeverDestroyed.h>
+#include <wtf/StdLibExtras.h>
 #include <wtf/dtoa.h>
 #include <wtf/text/StringBuffer.h>
 #include <wtf/text/StringBuilder.h>
 #include <wtf/text/StringImpl.h>
 
-#if ENABLE(CSS_IMAGE_SET)
-#include "CSSImageSetValue.h"
+#if ENABLE(CSS_GRID_LAYOUT)
+#include "CSSGridLineNamesValue.h"
+#include "CSSGridTemplateAreasValue.h"
 #endif
 
-#if ENABLE(CSS_FILTERS)
-#include "WebKitCSSFilterValue.h"
-#if ENABLE(SVG)
-#include "WebKitCSSSVGDocumentValue.h"
-#endif
+#if ENABLE(CSS_IMAGE_SET)
+#include "CSSImageSetValue.h"
 #endif
 
-#if ENABLE(CSS_SHADERS)
-#include "WebKitCSSArrayFunctionValue.h"
-#include "WebKitCSSMatFunctionValue.h"
-#include "WebKitCSSMixFunctionValue.h"
-#include "WebKitCSSShaderValue.h"
+#if ENABLE(CSS_SCROLL_SNAP)
+#include "LengthRepeat.h"
 #endif
 
 #if ENABLE(DASHBOARD_SUPPORT)
@@ -123,7 +133,6 @@ extern int cssyydebug;
 
 extern int cssyyparse(WebCore::CSSParser*);
 
-using namespace std;
 using namespace WTF;
 
 namespace {
@@ -136,19 +145,19 @@ enum PropertyType {
 class ImplicitScope {
     WTF_MAKE_NONCOPYABLE(ImplicitScope);
 public:
-    ImplicitScope(WebCore::CSSParser* parser, PropertyType propertyType)
+    ImplicitScope(WebCore::CSSParser& parser, PropertyType propertyType)
         : m_parser(parser)
     {
-        m_parser->m_implicitShorthand = propertyType == PropertyImplicit;
+        m_parser.m_implicitShorthand = propertyType == PropertyImplicit;
     }
 
     ~ImplicitScope()
     {
-        m_parser->m_implicitShorthand = false;
+        m_parser.m_implicitShorthand = false;
     }
 
 private:
-    WebCore::CSSParser* m_parser;
+    WebCore::CSSParser& m_parser;
 };
 
 } // namespace
@@ -158,31 +167,10 @@ namespace WebCore {
 static const unsigned INVALID_NUM_PARSED_PROPERTIES = UINT_MAX;
 static const double MAX_SCALE = 1000000;
 
-template <unsigned N>
-static bool equal(const CSSParserString& a, const char (&b)[N])
+template<unsigned length> bool equalLettersIgnoringASCIICase(const CSSParserValue& value, const char (&lowercaseLetters)[length])
 {
-    unsigned length = N - 1; // Ignore the trailing null character
-    if (a.length() != length)
-        return false;
-
-    return a.is8Bit() ? WTF::equal(a.characters8(), reinterpret_cast<const LChar*>(b), length) : WTF::equal(a.characters16(), reinterpret_cast<const LChar*>(b), length);
-}
-
-template <unsigned N>
-static bool equalIgnoringCase(const CSSParserString& a, const char (&b)[N])
-{
-    unsigned length = N - 1; // Ignore the trailing null character
-    if (a.length() != length)
-        return false;
-
-    return a.is8Bit() ? WTF::equalIgnoringCase(b, a.characters8(), length) : WTF::equalIgnoringCase(b, a.characters16(), length);
-}
-
-template <unsigned N>
-static bool equalIgnoringCase(CSSParserValue* value, const char (&b)[N])
-{
-    ASSERT(value->unit == CSSPrimitiveValue::CSS_IDENT || value->unit == CSSPrimitiveValue::CSS_STRING);
-    return equalIgnoringCase(value->string, b);
+    ASSERT(value.unit == CSSPrimitiveValue::CSS_IDENT || value.unit == CSSPrimitiveValue::CSS_STRING);
+    return equalLettersIgnoringASCIICase(value.string, lowercaseLetters);
 }
 
 static bool hasPrefix(const char* string, unsigned length, const char* prefix)
@@ -196,9 +184,10 @@ static bool hasPrefix(const char* string, unsigned length, const char* prefix)
     return false;
 }
 
-static PassRefPtr<CSSPrimitiveValue> createPrimitiveValuePair(PassRefPtr<CSSPrimitiveValue> first, PassRefPtr<CSSPrimitiveValue> second)
+template<typename... Args>
+static Ref<CSSPrimitiveValue> createPrimitiveValuePair(Args&&... args)
 {
-    return cssValuePool().createValue(Pair::create(first, second));
+    return CSSValuePool::singleton().createValue(Pair::create(std::forward<Args>(args)...));
 }
 
 class AnimationParseContext {
@@ -248,45 +237,45 @@ private:
 
 const CSSParserContext& strictCSSParserContext()
 {
-    DEFINE_STATIC_LOCAL(CSSParserContext, strictContext, (CSSStrictMode));
+    static NeverDestroyed<CSSParserContext> strictContext(CSSStrictMode);
     return strictContext;
 }
 
-CSSParserContext::CSSParserContext(CSSParserMode mode, const KURL& baseURL)
+CSSParserContext::CSSParserContext(CSSParserMode mode, const URL& baseURL)
     : baseURL(baseURL)
     , mode(mode)
     , isHTMLDocument(false)
-    , isCSSCustomFilterEnabled(false)
-    , isCSSStickyPositionEnabled(false)
-    , isCSSRegionsEnabled(false)
-    , isCSSCompositingEnabled(false)
-    , isCSSGridLayoutEnabled(false)
-#if ENABLE(CSS_VARIABLES)
-    , isCSSVariablesEnabled(false)
-#endif
+    , isCSSRegionsEnabled(RuntimeEnabledFeatures::sharedFeatures().cssRegionsEnabled())
+    , isCSSCompositingEnabled(RuntimeEnabledFeatures::sharedFeatures().cssCompositingEnabled())
     , needsSiteSpecificQuirks(false)
     , enforcesCSSMIMETypeInNoQuirksMode(true)
     , useLegacyBackgroundSizeShorthandBehavior(false)
 {
+#if PLATFORM(IOS)
+    // FIXME: Force the site specific quirk below to work on iOS. Investigating other site specific quirks
+    // to see if we can enable the preference all together is to be handled by:
+    // <rdar://problem/8493309> Investigate Enabling Site Specific Quirks in MobileSafari and UIWebView
+    needsSiteSpecificQuirks = true;
+#endif
 }
 
-CSSParserContext::CSSParserContext(Document* document, const KURL& baseURL, const String& charset)
-    : baseURL(baseURL.isNull() ? document->baseURL() : baseURL)
+CSSParserContext::CSSParserContext(Document& document, const URL& baseURL, const String& charset)
+    : baseURL(baseURL.isNull() ? document.baseURL() : baseURL)
     , charset(charset)
-    , mode(document->inQuirksMode() ? CSSQuirksMode : CSSStrictMode)
-    , isHTMLDocument(document->isHTMLDocument())
-    , isCSSCustomFilterEnabled(document->settings() ? document->settings()->isCSSCustomFilterEnabled() : false)
-    , isCSSStickyPositionEnabled(document->cssStickyPositionEnabled())
-    , isCSSRegionsEnabled(document->cssRegionsEnabled())
-    , isCSSCompositingEnabled(document->cssCompositingEnabled())
-    , isCSSGridLayoutEnabled(document->cssGridLayoutEnabled())
-#if ENABLE(CSS_VARIABLES)
-    , isCSSVariablesEnabled(document->settings() ? document->settings()->cssVariablesEnabled() : false)
-#endif
-    , needsSiteSpecificQuirks(document->settings() ? document->settings()->needsSiteSpecificQuirks() : false)
-    , enforcesCSSMIMETypeInNoQuirksMode(!document->settings() || document->settings()->enforceCSSMIMETypeInNoQuirksMode())
-    , useLegacyBackgroundSizeShorthandBehavior(document->settings() ? document->settings()->useLegacyBackgroundSizeShorthandBehavior() : false)
+    , mode(document.inQuirksMode() ? CSSQuirksMode : CSSStrictMode)
+    , isHTMLDocument(document.isHTMLDocument())
+    , isCSSRegionsEnabled(document.cssRegionsEnabled())
+    , isCSSCompositingEnabled(document.cssCompositingEnabled())
+    , needsSiteSpecificQuirks(document.settings() ? document.settings()->needsSiteSpecificQuirks() : false)
+    , enforcesCSSMIMETypeInNoQuirksMode(!document.settings() || document.settings()->enforceCSSMIMETypeInNoQuirksMode())
+    , useLegacyBackgroundSizeShorthandBehavior(document.settings() ? document.settings()->useLegacyBackgroundSizeShorthandBehavior() : false)
 {
+#if PLATFORM(IOS)
+    // FIXME: Force the site specific quirk below to work on iOS. Investigating other site specific quirks
+    // to see if we can enable the preference all together is to be handled by:
+    // <rdar://problem/8493309> Investigate Enabling Site Specific Quirks in MobileSafari and UIWebView
+    needsSiteSpecificQuirks = true;
+#endif
 }
 
 bool operator==(const CSSParserContext& a, const CSSParserContext& b)
@@ -295,14 +284,8 @@ bool operator==(const CSSParserContext& a, const CSSParserContext& b)
         && a.charset == b.charset
         && a.mode == b.mode
         && a.isHTMLDocument == b.isHTMLDocument
-        && a.isCSSCustomFilterEnabled == b.isCSSCustomFilterEnabled
-        && a.isCSSStickyPositionEnabled == b.isCSSStickyPositionEnabled
         && a.isCSSRegionsEnabled == b.isCSSRegionsEnabled
         && a.isCSSCompositingEnabled == b.isCSSCompositingEnabled
-        && a.isCSSGridLayoutEnabled == b.isCSSGridLayoutEnabled
-#if ENABLE(CSS_VARIABLES)
-        && a.isCSSVariablesEnabled == b.isCSSVariablesEnabled
-#endif
         && a.needsSiteSpecificQuirks == b.needsSiteSpecificQuirks
         && a.enforcesCSSMIMETypeInNoQuirksMode == b.enforcesCSSMIMETypeInNoQuirksMode
         && a.useLegacyBackgroundSizeShorthandBehavior == b.useLegacyBackgroundSizeShorthandBehavior;
@@ -312,35 +295,34 @@ CSSParser::CSSParser(const CSSParserContext& context)
     : m_context(context)
     , m_important(false)
     , m_id(CSSPropertyInvalid)
-    , m_styleSheet(0)
-#if ENABLE(CSS3_CONDITIONAL_RULES)
+    , m_styleSheet(nullptr)
     , m_supportsCondition(false)
-#endif
-    , m_selectorListForParseSelector(0)
+    , m_selectorListForParseSelector(nullptr)
     , m_numParsedPropertiesBeforeMarginBox(INVALID_NUM_PARSED_PROPERTIES)
     , m_inParseShorthand(0)
     , m_currentShorthand(CSSPropertyInvalid)
     , m_implicitShorthand(false)
-    , m_hasFontFaceOnlyValues(false)
     , m_hadSyntacticallyValidCSSRule(false)
     , m_logErrors(false)
     , m_ignoreErrorsInDeclaration(false)
-#if ENABLE(CSS_SHADERS)
-    , m_inFilterRule(false)
-#endif
     , m_defaultNamespace(starAtom)
     , m_parsedTextPrefixLength(0)
+    , m_nestedSelectorLevel(0)
     , m_propertyRange(UINT_MAX, UINT_MAX)
-    , m_ruleSourceDataResult(0)
+    , m_ruleSourceDataResult(nullptr)
     , m_parsingMode(NormalMode)
     , m_is8BitSource(false)
-    , m_currentCharacter8(0)
-    , m_currentCharacter16(0)
+    , m_currentCharacter8(nullptr)
+    , m_currentCharacter16(nullptr)
     , m_length(0)
     , m_token(0)
     , m_lineNumber(0)
     , m_tokenStartLineNumber(0)
+    , m_tokenStartColumnNumber(0)
     , m_lastSelectorLineNumber(0)
+    , m_columnOffsetForLine(0)
+    , m_sheetStartLineNumber(0)
+    , m_sheetStartColumnNumber(0)
     , m_allowImportRules(true)
     , m_allowNamespaceDeclarations(true)
 #if ENABLE(CSS_DEVICE_ADAPTATION)
@@ -350,59 +332,29 @@ CSSParser::CSSParser(const CSSParserContext& context)
 #if YYDEBUG > 0
     cssyydebug = 1;
 #endif
-    m_tokenStart.ptr8 = 0;
+    m_tokenStart.ptr8 = nullptr;
 }
 
 CSSParser::~CSSParser()
 {
     clearProperties();
-
-    deleteAllValues(m_floatingSelectors);
-    deleteAllValues(m_floatingSelectorVectors);
-    deleteAllValues(m_floatingValueLists);
-    deleteAllValues(m_floatingFunctions);
 }
 
-template <typename CharacterType>
-ALWAYS_INLINE static void makeLower(const CharacterType* input, CharacterType* output, unsigned length)
+template<typename CharacterType> ALWAYS_INLINE static void convertToASCIILowercaseInPlace(CharacterType* characters, unsigned length)
 {
-    // FIXME: If we need Unicode lowercasing here, then we probably want the real kind
-    // that can potentially change the length of the string rather than the character
-    // by character kind. If we don't need Unicode lowercasing, it would be good to
-    // simplify this function.
-
-    if (charactersAreAllASCII(input, length)) {
-        // Fast case for all-ASCII.
-        for (unsigned i = 0; i < length; i++)
-            output[i] = toASCIILower(input[i]);
-    } else {
-        for (unsigned i = 0; i < length; i++)
-            output[i] = Unicode::toLower(input[i]);
-    }
-}
-
-void CSSParserString::lower()
-{
-    if (is8Bit()) {
-        makeLower(characters8(), characters8(), length());
-        return;
-    }
-
-    makeLower(characters16(), characters16(), length());
+    for (unsigned i = 0; i < length; ++i)
+        characters[i] = toASCIILower(characters[i]);
 }
 
-#if ENABLE(CSS_VARIABLES)
-AtomicString CSSParserString::substring(unsigned position, unsigned length) const
+void CSSParserString::convertToASCIILowercaseInPlace()
 {
-    ASSERT(m_length >= position + length);
-
     if (is8Bit())
-        return AtomicString(characters8() + position, length);
-    return AtomicString(characters16() + position, length);
+        WebCore::convertToASCIILowercaseInPlace(characters8(), length());
+    else
+        WebCore::convertToASCIILowercaseInPlace(characters16(), length());
 }
-#endif
 
-void CSSParser::setupParser(const char* prefix, unsigned prefixLength, const String& string, const char* suffix, unsigned suffixLength)
+void CSSParser::setupParser(const char* prefix, unsigned prefixLength, StringView string, const char* suffix, unsigned suffixLength)
 {
     m_parsedTextPrefixLength = prefixLength;
     unsigned stringLength = string.length();
@@ -410,8 +362,8 @@ void CSSParser::setupParser(const char* prefix, unsigned prefixLength, const Str
     m_length = length;
 
     if (!stringLength || string.is8Bit()) {
-        m_dataStart8 = adoptArrayPtr(new LChar[length]);
-        for (unsigned i = 0; i < m_parsedTextPrefixLength; i++)
+        m_dataStart8 = std::make_unique<LChar[]>(length);
+        for (unsigned i = 0; i < m_parsedTextPrefixLength; ++i)
             m_dataStart8[i] = prefix[i];
 
         if (stringLength)
@@ -422,18 +374,18 @@ void CSSParser::setupParser(const char* prefix, unsigned prefixLength, const Str
         for (unsigned i = start; i < end; i++)
             m_dataStart8[i] = suffix[i - start];
 
-        m_dataStart8[length - 1] = 0;
+        m_dataStart8[length - 1] = '\0';
 
         m_is8BitSource = true;
         m_currentCharacter8 = m_dataStart8.get();
-        m_currentCharacter16 = 0;
+        m_currentCharacter16 = nullptr;
         setTokenStart<LChar>(m_currentCharacter8);
         m_lexFunc = &CSSParser::realLex<LChar>;
         return;
     }
 
-    m_dataStart16 = adoptArrayPtr(new UChar[length]);
-    for (unsigned i = 0; i < m_parsedTextPrefixLength; i++)
+    m_dataStart16 = std::make_unique<UChar[]>(length);
+    for (unsigned i = 0; i < m_parsedTextPrefixLength; ++i)
         m_dataStart16[i] = prefix[i];
 
     ASSERT(stringLength);
@@ -444,62 +396,65 @@ void CSSParser::setupParser(const char* prefix, unsigned prefixLength, const Str
     for (unsigned i = start; i < end; i++)
         m_dataStart16[i] = suffix[i - start];
 
-    m_dataStart16[length - 1] = 0;
+    m_dataStart16[length - 1] = '\0';
 
     m_is8BitSource = false;
-    m_currentCharacter8 = 0;
+    m_currentCharacter8 = nullptr;
     m_currentCharacter16 = m_dataStart16.get();
     setTokenStart<UChar>(m_currentCharacter16);
     m_lexFunc = &CSSParser::realLex<UChar>;
 }
 
-void CSSParser::parseSheet(StyleSheetContents* sheet, const String& string, int startLineNumber, RuleSourceDataList* ruleSourceDataResult, bool logErrors)
+void CSSParser::parseSheet(StyleSheetContents* sheet, const String& string, const TextPosition& textPosition, RuleSourceDataList* ruleSourceDataResult, bool logErrors)
 {
     setStyleSheet(sheet);
     m_defaultNamespace = starAtom; // Reset the default namespace.
     if (ruleSourceDataResult)
-        m_currentRuleDataStack = adoptPtr(new RuleSourceDataList());
+        m_currentRuleDataStack = std::make_unique<RuleSourceDataList>();
     m_ruleSourceDataResult = ruleSourceDataResult;
 
     m_logErrors = logErrors && sheet->singleOwnerDocument() && !sheet->baseURL().isEmpty() && sheet->singleOwnerDocument()->page();
     m_ignoreErrorsInDeclaration = false;
-    m_lineNumber = startLineNumber;
+    m_sheetStartLineNumber = textPosition.m_line.zeroBasedInt();
+    m_sheetStartColumnNumber = textPosition.m_column.zeroBasedInt();
+    m_lineNumber = m_sheetStartLineNumber;
+    m_columnOffsetForLine = 0;
     setupParser("", string, "");
     cssyyparse(this);
     sheet->shrinkToFit();
-    m_currentRuleDataStack.clear();
-    m_ruleSourceDataResult = 0;
-    m_rule = 0;
+    m_currentRuleDataStack.reset();
+    m_ruleSourceDataResult = nullptr;
+    m_rule = nullptr;
     m_ignoreErrorsInDeclaration = false;
     m_logErrors = false;
 }
 
-PassRefPtr<StyleRuleBase> CSSParser::parseRule(StyleSheetContents* sheet, const String& string)
+RefPtr<StyleRuleBase> CSSParser::parseRule(StyleSheetContents* sheet, const String& string)
 {
     setStyleSheet(sheet);
     m_allowNamespaceDeclarations = false;
     setupParser("@-webkit-rule{", string, "} ");
     cssyyparse(this);
-    return m_rule.release();
+    return m_rule;
 }
 
-PassRefPtr<StyleKeyframe> CSSParser::parseKeyframeRule(StyleSheetContents* sheet, const String& string)
+RefPtr<StyleKeyframe> CSSParser::parseKeyframeRule(StyleSheetContents* sheet, const String& string)
 {
     setStyleSheet(sheet);
     setupParser("@-webkit-keyframe-rule{ ", string, "} ");
     cssyyparse(this);
-    return m_keyframe.release();
+    return m_keyframe;
 }
 
-#if ENABLE(CSS3_CONDITIONAL_RULES)
 bool CSSParser::parseSupportsCondition(const String& string)
 {
     m_supportsCondition = false;
-    setupParser("@-webkit-supports-condition{ ", string, "} ");
+    // can't use { because tokenizer state switches from supports to initial state when it sees { token.
+    // instead insert one " " (which is WHITESPACE in CSSGrammar.y)
+    setupParser("@-webkit-supports-condition ", string, "} ");
     cssyyparse(this);
     return m_supportsCondition;
 }
-#endif
 
 static inline bool isColorPropertyID(CSSPropertyID propertyId)
 {
@@ -518,10 +473,8 @@ static inline bool isColorPropertyID(CSSPropertyID propertyId)
     case CSSPropertyWebkitBorderBeforeColor:
     case CSSPropertyWebkitBorderEndColor:
     case CSSPropertyWebkitBorderStartColor:
-    case CSSPropertyWebkitColumnRuleColor:
-#if ENABLE(CSS3_TEXT)
+    case CSSPropertyColumnRuleColor:
     case CSSPropertyWebkitTextDecorationColor:
-#endif // CSS3_TEXT
     case CSSPropertyWebkitTextEmphasisColor:
     case CSSPropertyWebkitTextFillColor:
     case CSSPropertyWebkitTextStrokeColor:
@@ -531,36 +484,38 @@ static inline bool isColorPropertyID(CSSPropertyID propertyId)
     }
 }
 
-static bool parseColorValue(MutableStylePropertySet* declaration, CSSPropertyID propertyId, const String& string, bool important, CSSParserMode cssParserMode)
+bool CSSParser::isValidSystemColorValue(CSSValueID valueID)
+{
+    return valueID >= CSSValueAqua && valueID <= CSSValueAppleSystemYellow;
+}
+
+static bool validPrimitiveValueColor(CSSValueID valueID, bool strict = false)
+{
+    return (valueID == CSSValueWebkitText || valueID == CSSValueCurrentcolor || valueID == CSSValueMenu
+        || CSSParser::isValidSystemColorValue(valueID) || valueID == CSSValueAlpha
+        || (valueID >= CSSValueWebkitFocusRingColor && valueID < CSSValueWebkitText && !strict));
+}
+
+static CSSParser::ParseResult parseColorValue(MutableStyleProperties* declaration, CSSPropertyID propertyId, const String& string, bool important, CSSParserMode cssParserMode)
 {
     ASSERT(!string.isEmpty());
     bool strict = isStrictParserMode(cssParserMode);
     if (!isColorPropertyID(propertyId))
-        return false;
+        return CSSParser::ParseResult::Error;
+
     CSSParserString cssString;
     cssString.init(string);
     CSSValueID valueID = cssValueKeywordID(cssString);
-    bool validPrimitive = false;
-    if (valueID == CSSValueWebkitText)
-        validPrimitive = true;
-    else if (valueID == CSSValueCurrentcolor)
-        validPrimitive = true;
-    else if ((valueID >= CSSValueAqua && valueID <= CSSValueWindowtext) || valueID == CSSValueMenu
-             || (valueID >= CSSValueWebkitFocusRingColor && valueID < CSSValueWebkitText && !strict)) {
-        validPrimitive = true;
-    }
-
-    if (validPrimitive) {
-        RefPtr<CSSValue> value = cssValuePool().createIdentifierValue(valueID);
-        declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important));
-        return true;
+    if (validPrimitiveValueColor(valueID, strict)) {
+        RefPtr<CSSValue> value = CSSValuePool::singleton().createIdentifierValue(valueID);
+        return declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important)) ? CSSParser::ParseResult::Changed : CSSParser::ParseResult::Unchanged;
     }
     RGBA32 color;
     if (!CSSParser::fastParseColor(color, string, strict && string[0] != '#'))
-        return false;
-    RefPtr<CSSValue> value = cssValuePool().createColorValue(color);
-    declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important));
-    return true;
+        return CSSParser::ParseResult::Error;
+
+    RefPtr<CSSValue> value = CSSValuePool::singleton().createColorValue(color);
+    return declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important)) ? CSSParser::ParseResult::Changed : CSSParser::ParseResult::Unchanged;
 }
 
 static inline bool isSimpleLengthPropertyID(CSSPropertyID propertyId, bool& acceptsNegativeNumbers)
@@ -583,26 +538,36 @@ static inline bool isSimpleLengthPropertyID(CSSPropertyID propertyId, bool& acce
     case CSSPropertyWebkitPaddingBefore:
     case CSSPropertyWebkitPaddingEnd:
     case CSSPropertyWebkitPaddingStart:
+#if ENABLE(CSS_GRID_LAYOUT)
+    case CSSPropertyWebkitGridColumnGap:
+    case CSSPropertyWebkitGridRowGap:
+#endif
         acceptsNegativeNumbers = false;
         return true;
 #if ENABLE(CSS_SHAPES)
     case CSSPropertyWebkitShapeMargin:
-    case CSSPropertyWebkitShapePadding:
         acceptsNegativeNumbers = false;
-        return RuntimeEnabledFeatures::cssShapesEnabled();
+        return RuntimeEnabledFeatures::sharedFeatures().cssShapesEnabled();
 #endif
     case CSSPropertyBottom:
+    case CSSPropertyCx:
+    case CSSPropertyCy:
     case CSSPropertyLeft:
     case CSSPropertyMarginBottom:
     case CSSPropertyMarginLeft:
     case CSSPropertyMarginRight:
     case CSSPropertyMarginTop:
+    case CSSPropertyR:
+    case CSSPropertyRx:
+    case CSSPropertyRy:
     case CSSPropertyRight:
     case CSSPropertyTop:
     case CSSPropertyWebkitMarginAfter:
     case CSSPropertyWebkitMarginBefore:
     case CSSPropertyWebkitMarginEnd:
     case CSSPropertyWebkitMarginStart:
+    case CSSPropertyX:
+    case CSSPropertyY:
         acceptsNegativeNumbers = true;
         return true;
     default:
@@ -629,12 +594,12 @@ static inline bool parseSimpleLength(const CharacterType* characters, unsigned&
     return ok;
 }
 
-static bool parseSimpleLengthValue(MutableStylePropertySet* declaration, CSSPropertyID propertyId, const String& string, bool important, CSSParserMode cssParserMode)
+static CSSParser::ParseResult parseSimpleLengthValue(MutableStyleProperties* declaration, CSSPropertyID propertyId, const String& string, bool important, CSSParserMode cssParserMode)
 {
     ASSERT(!string.isEmpty());
     bool acceptsNegativeNumbers;
     if (!isSimpleLengthPropertyID(propertyId, acceptsNegativeNumbers))
-        return false;
+        return CSSParser::ParseResult::Error;
 
     unsigned length = string.length();
     double number;
@@ -642,26 +607,27 @@ static bool parseSimpleLengthValue(MutableStylePropertySet* declaration, CSSProp
 
     if (string.is8Bit()) {
         if (!parseSimpleLength(string.characters8(), length, unit, number))
-            return false;
+            return CSSParser::ParseResult::Error;
     } else {
         if (!parseSimpleLength(string.characters16(), length, unit, number))
-            return false;
+            return CSSParser::ParseResult::Error;
     }
 
     if (unit == CSSPrimitiveValue::CSS_NUMBER) {
         if (number && isStrictParserMode(cssParserMode))
-            return false;
+            return CSSParser::ParseResult::Error;
         unit = CSSPrimitiveValue::CSS_PX;
     }
     if (number < 0 && !acceptsNegativeNumbers)
-        return false;
+        return CSSParser::ParseResult::Error;
+    if (std::isinf(number))
+        return CSSParser::ParseResult::Error;
 
-    RefPtr<CSSValue> value = cssValuePool().createValue(number, unit);
-    declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important));
-    return true;
+    RefPtr<CSSValue> value = CSSValuePool::singleton().createValue(number, unit);
+    return declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important)) ? CSSParser::ParseResult::Changed : CSSParser::ParseResult::Unchanged;
 }
 
-static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int valueID, const CSSParserContext& parserContext)
+static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int valueID, const CSSParserContext& parserContext, StyleSheetContents* styleSheetContents)
 {
     if (!valueID)
         return false;
@@ -679,7 +645,7 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
     case CSSPropertyWebkitBorderBeforeStyle:
     case CSSPropertyWebkitBorderEndStyle:
     case CSSPropertyWebkitBorderStartStyle:
-    case CSSPropertyWebkitColumnRuleStyle:
+    case CSSPropertyColumnRuleStyle:
         if (valueID >= CSSValueNone && valueID <= CSSValueDouble)
             return true;
         break;
@@ -700,14 +666,16 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
             return true;
         break;
     case CSSPropertyDisplay:
-        // inline | block | list-item | run-in | inline-block | table |
+        // inline | block | list-item | inline-block | table |
         // inline-table | table-row-group | table-header-group | table-footer-group | table-row |
         // table-column-group | table-column | table-cell | table-caption | -webkit-box | -webkit-inline-box | none | inherit
-        // -webkit-flex | -webkit-inline-flex | -webkit-grid | -webkit-inline-grid
+        // flex | -webkit-flex | inline-flex | -webkit-inline-flex | -webkit-grid | -webkit-inline-grid
         if ((valueID >= CSSValueInline && valueID <= CSSValueWebkitInlineFlex) || valueID == CSSValueNone)
             return true;
-        if (parserContext.isCSSGridLayoutEnabled && (valueID == CSSValueWebkitGrid || valueID == CSSValueWebkitInlineGrid))
+#if ENABLE(CSS_GRID_LAYOUT)
+        if (valueID == CSSValueWebkitGrid || valueID == CSSValueWebkitInlineGrid)
             return true;
+#endif
         break;
 
     case CSSPropertyEmptyCells: // show | hide | inherit
@@ -722,9 +690,10 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueNormal || valueID == CSSValueItalic || valueID == CSSValueOblique)
             return true;
         break;
-    case CSSPropertyImageRendering: // auto | optimizeSpeed | optimizeQuality | -webkit-crisp-edges | -webkit-optimize-contrast
+    case CSSPropertyImageRendering: // auto | optimizeSpeed | optimizeQuality | -webkit-crisp-edges | -webkit-optimize-contrast | crisp-edges | pixelated
+        // optimizeSpeed and optimizeQuality are deprecated; a user agent must accept them as valid values but must treat them as having the same behavior as pixelated and auto respectively.
         if (valueID == CSSValueAuto || valueID == CSSValueOptimizespeed || valueID == CSSValueOptimizequality
-            || valueID == CSSValueWebkitCrispEdges || valueID == CSSValueWebkitOptimizeContrast)
+            || valueID == CSSValueWebkitCrispEdges || valueID == CSSValueWebkitOptimizeContrast || valueID == CSSValueCrispEdges || valueID == CSSValuePixelated)
             return true;
         break;
     case CSSPropertyListStylePosition: // inside | outside | inherit
@@ -737,6 +706,10 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if ((valueID >= CSSValueDisc && valueID <= CSSValueKatakanaIroha) || valueID == CSSValueNone)
             return true;
         break;
+    case CSSPropertyObjectFit:
+        if (valueID == CSSValueFill || valueID == CSSValueContain || valueID == CSSValueCover || valueID == CSSValueNone || valueID == CSSValueScaleDown)
+            return true;
+        break;
     case CSSPropertyOutlineStyle: // (<border-style> except hidden) | auto | inherit
         if (valueID == CSSValueAuto || valueID == CSSValueNone || (valueID >= CSSValueInset && valueID <= CSSValueDouble))
             return true;
@@ -746,6 +719,18 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueNormal || valueID == CSSValueBreakWord)
             return true;
         break;
+#if ENABLE(TOUCH_EVENTS)
+    case CSSPropertyTouchAction: // auto | manipulation
+        if (valueID == CSSValueAuto || valueID == CSSValueManipulation)
+            return true;
+        break;
+#endif
+#if ENABLE(CSS_SCROLL_SNAP)
+    case CSSPropertyWebkitScrollSnapType: // none | mandatory | proximity
+        if (valueID == CSSValueNone || valueID == CSSValueMandatory || valueID == CSSValueProximity)
+            return true;
+        break;
+#endif
     case CSSPropertyOverflowX: // visible | hidden | scroll | auto | marquee | overlay | inherit
         if (valueID == CSSValueVisible || valueID == CSSValueHidden || valueID == CSSValueScroll || valueID == CSSValueAuto || valueID == CSSValueOverlay || valueID == CSSValueWebkitMarquee)
             return true;
@@ -773,11 +758,7 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
             return true;
         break;
     case CSSPropertyPosition: // static | relative | absolute | fixed | sticky | inherit
-        if (valueID == CSSValueStatic || valueID == CSSValueRelative || valueID == CSSValueAbsolute || valueID == CSSValueFixed
-#if ENABLE(CSS_STICKY_POSITION)
-            || (parserContext.isCSSStickyPositionEnabled && valueID == CSSValueWebkitSticky)
-#endif
-            )
+        if (valueID == CSSValueStatic || valueID == CSSValueRelative || valueID == CSSValueAbsolute || valueID == CSSValueFixed || valueID == CSSValueWebkitSticky)
             return true;
         break;
     case CSSPropertyResize: // none | both | horizontal | vertical | auto
@@ -821,7 +802,7 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
             return true;
         break;
     case CSSPropertyWebkitAppearance:
-        if ((valueID >= CSSValueCheckbox && valueID <= CSSValueTextarea) || valueID == CSSValueNone)
+        if ((valueID >= CSSValueCheckbox && valueID <= CSSValueCapsLockIndicator) || valueID == CSSValueNone)
             return true;
         break;
     case CSSPropertyWebkitBackfaceVisibility:
@@ -829,12 +810,15 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
             return true;
         break;
 #if ENABLE(CSS_COMPOSITING)
-    case CSSPropertyWebkitBlendMode:
+    case CSSPropertyMixBlendMode:
         if (parserContext.isCSSCompositingEnabled && (valueID == CSSValueNormal || valueID == CSSValueMultiply || valueID == CSSValueScreen
             || valueID == CSSValueOverlay || valueID == CSSValueDarken || valueID == CSSValueLighten ||  valueID == CSSValueColorDodge
             || valueID == CSSValueColorBurn || valueID == CSSValueHardLight || valueID == CSSValueSoftLight || valueID == CSSValueDifference
-            || valueID == CSSValueExclusion || valueID == CSSValueHue || valueID == CSSValueSaturation || valueID == CSSValueColor
-            || valueID == CSSValueLuminosity))
+            || valueID == CSSValueExclusion || valueID == CSSValuePlusDarker || valueID == CSSValuePlusLighter))
+            return true;
+        break;
+    case CSSPropertyIsolation:
+        if (parserContext.isCSSCompositingEnabled && (valueID == CSSValueAuto || valueID == CSSValueIsolate))
             return true;
         break;
 #endif
@@ -868,34 +852,18 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueStart || valueID == CSSValueEnd || valueID == CSSValueCenter || valueID == CSSValueJustify)
             return true;
         break;
-    case CSSPropertyWebkitColorCorrection:
-        if (valueID == CSSValueSrgb || valueID == CSSValueDefault)
+    case CSSPropertyColumnFill:
+        if (valueID == CSSValueAuto || valueID == CSSValueBalance)
             return true;
         break;
-    case CSSPropertyWebkitAlignContent:
-         if (valueID == CSSValueFlexStart || valueID == CSSValueFlexEnd || valueID == CSSValueCenter || valueID == CSSValueSpaceBetween || valueID == CSSValueSpaceAround || valueID == CSSValueStretch)
-             return true;
-         break;
-    case CSSPropertyWebkitAlignItems:
-        if (valueID == CSSValueFlexStart || valueID == CSSValueFlexEnd || valueID == CSSValueCenter || valueID == CSSValueBaseline || valueID == CSSValueStretch)
-            return true;
-        break;
-    case CSSPropertyWebkitAlignSelf:
-        if (valueID == CSSValueAuto || valueID == CSSValueFlexStart || valueID == CSSValueFlexEnd || valueID == CSSValueCenter || valueID == CSSValueBaseline || valueID == CSSValueStretch)
-            return true;
-        break;
-    case CSSPropertyWebkitFlexDirection:
+    case CSSPropertyFlexDirection:
         if (valueID == CSSValueRow || valueID == CSSValueRowReverse || valueID == CSSValueColumn || valueID == CSSValueColumnReverse)
             return true;
         break;
-    case CSSPropertyWebkitFlexWrap:
+    case CSSPropertyFlexWrap:
         if (valueID == CSSValueNowrap || valueID == CSSValueWrap || valueID == CSSValueWrapReverse)
              return true;
         break;
-    case CSSPropertyWebkitJustifyContent:
-        if (valueID == CSSValueFlexStart || valueID == CSSValueFlexEnd || valueID == CSSValueCenter || valueID == CSSValueSpaceBetween || valueID == CSSValueSpaceAround)
-            return true;
-        break;
     case CSSPropertyWebkitFontKerning:
         if (valueID == CSSValueAuto || valueID == CSSValueNormal || valueID == CSSValueNone)
             return true;
@@ -908,10 +876,6 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueNone || valueID == CSSValueManual || valueID == CSSValueAuto)
             return true;
         break;
-    case CSSPropertyWebkitGridAutoFlow:
-        if (valueID == CSSValueNone || valueID == CSSValueRow || valueID == CSSValueColumn)
-            return true;
-        break;
     case CSSPropertyWebkitLineAlign:
         if (valueID == CSSValueNone || valueID == CSSValueEdges)
             return true;
@@ -975,7 +939,7 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         break;
 
     case CSSPropertyWebkitRubyPosition:
-        if (valueID == CSSValueBefore || valueID == CSSValueAfter)
+        if (valueID == CSSValueBefore || valueID == CSSValueAfter || valueID == CSSValueInterCharacter)
             return true;
         break;
 
@@ -990,14 +954,10 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueNone || valueID == CSSValueHorizontal)
             return true;
         break;
-    case CSSPropertyWebkitTextEmphasisPosition:
-        if (valueID == CSSValueOver || valueID == CSSValueUnder)
-            return true;
-        break;
 #if ENABLE(CSS3_TEXT)
     case CSSPropertyWebkitTextJustify:
-        // auto | none | inter-word | inter-ideograph | inter-cluster | distribute | kashida
-        if ((valueID >= CSSValueInterWord && valueID <= CSSValueKashida) || valueID == CSSValueAuto || valueID == CSSValueNone)
+        // auto | none | inter-word | distribute
+        if (valueID == CSSValueInterWord || valueID == CSSValueDistribute || valueID == CSSValueAuto || valueID == CSSValueNone)
             return true;
         break;
 #endif // CSS3_TEXT
@@ -1006,6 +966,13 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueDisc || valueID == CSSValueCircle || valueID == CSSValueSquare || valueID == CSSValueNone)
             return true;
         break;
+#if ENABLE(IOS_TEXT_AUTOSIZING)
+    case CSSPropertyWebkitTextSizeAdjust:
+        if (valueID == CSSValueAuto || valueID == CSSValueNone)
+            return true;
+        break;
+#endif
+    case CSSPropertyTransformStyle:
     case CSSPropertyWebkitTransformStyle:
         if (valueID == CSSValueFlat || valueID == CSSValuePreserve3d)
             return true;
@@ -1015,27 +982,21 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
             return true;
         break;
     case CSSPropertyWebkitUserModify: // read-only | read-write
-        if (valueID == CSSValueReadOnly || valueID == CSSValueReadWrite || valueID == CSSValueReadWritePlaintextOnly)
+        if (valueID == CSSValueReadOnly || valueID == CSSValueReadWrite || valueID == CSSValueReadWritePlaintextOnly) {
+            if (styleSheetContents)
+                styleSheetContents->parserSetUsesStyleBasedEditability();
             return true;
+        }
         break;
     case CSSPropertyWebkitUserSelect: // auto | none | text | all
-        if (valueID == CSSValueAuto || valueID == CSSValueNone || valueID == CSSValueText || valueID == CSSValueAll)
-            return true;
-        break;
-#if ENABLE(CSS_EXCLUSIONS)
-    case CSSPropertyWebkitWrapFlow:
-        if (!RuntimeEnabledFeatures::cssExclusionsEnabled())
-            return false;
-        if (valueID == CSSValueAuto || valueID == CSSValueBoth || valueID == CSSValueStart || valueID == CSSValueEnd || valueID == CSSValueMaximum || valueID == CSSValueClear)
+        if (valueID == CSSValueAuto || valueID == CSSValueNone || valueID == CSSValueText)
             return true;
-        break;
-    case CSSPropertyWebkitWrapThrough:
-        if (!RuntimeEnabledFeatures::cssExclusionsEnabled())
-            return false;
-        if (valueID == CSSValueWrap || valueID == CSSValueNone)
+        if (valueID == CSSValueAll) {
+            if (styleSheetContents)
+                styleSheetContents->parserSetUsesStyleBasedEditability();
             return true;
+        }
         break;
-#endif
     case CSSPropertyWebkitWritingMode:
         if (valueID >= CSSValueHorizontalTb && valueID <= CSSValueHorizontalBt)
             return true;
@@ -1044,14 +1005,49 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueNormal || valueID == CSSValuePre || valueID == CSSValuePreWrap || valueID == CSSValuePreLine || valueID == CSSValueNowrap)
             return true;
         break;
-    case CSSPropertyWordBreak: // normal | break-all | break-word (this is a custom extension)
-        if (valueID == CSSValueNormal || valueID == CSSValueBreakAll || valueID == CSSValueBreakWord)
+    case CSSPropertyWordBreak: // normal | break-all | keep-all | break-word (this is a custom extension)
+        if (valueID == CSSValueNormal || valueID == CSSValueBreakAll || valueID == CSSValueKeepAll || valueID == CSSValueBreakWord)
+            return true;
+        break;
+#if ENABLE(CSS_TRAILING_WORD)
+    case CSSPropertyAppleTrailingWord: // auto | -apple-partially-balanced
+        if (valueID == CSSValueAuto || valueID == CSSValueWebkitPartiallyBalanced)
+            return true;
+        break;
+#endif
+    case CSSPropertyFontVariantPosition: // normal | sub | super
+        if (valueID == CSSValueNormal || valueID == CSSValueSub || valueID == CSSValueSuper)
+            return true;
+        break;
+    case CSSPropertyFontVariantCaps: // normal | small-caps | all-small-caps | petite-caps | all-petite-caps | unicase | titling-caps
+        if (valueID == CSSValueNormal || valueID == CSSValueSmallCaps || valueID == CSSValueAllSmallCaps || valueID == CSSValuePetiteCaps || valueID == CSSValueAllPetiteCaps || valueID == CSSValueUnicase || valueID == CSSValueTitlingCaps)
+            return true;
+        break;
+    case CSSPropertyFontVariantAlternates: // We only support the normal and historical-forms values.
+        if (valueID == CSSValueNormal || valueID == CSSValueHistoricalForms)
+            return true;
+        break;
+            
+    case CSSPropertyBreakAfter:
+    case CSSPropertyBreakBefore:
+        // auto | avoid | left | right | recto | verso | column | page | region | avoid-page | avoid-column | avoid-region
+        if (valueID == CSSValueAuto || valueID == CSSValueAvoid || valueID == CSSValueLeft || valueID == CSSValueRight
+            || valueID == CSSValueRecto || valueID == CSSValueVerso || valueID == CSSValueColumn || valueID == CSSValuePage
+            || valueID == CSSValueRegion || valueID == CSSValueAvoidColumn || valueID == CSSValueAvoidPage || valueID == CSSValueAvoidRegion)
+            return true;
+        break;
+    case CSSPropertyBreakInside:
+        // auto | avoid | avoid-page | avoid-column | avoid-region
+        if (valueID == CSSValueAuto || valueID == CSSValueAvoid || valueID == CSSValueAvoidColumn || valueID == CSSValueAvoidPage || valueID == CSSValueAvoidRegion)
             return true;
         break;
     default:
         ASSERT_NOT_REACHED();
         return false;
     }
+#if !ENABLE(CSS_COMPOSITING) && !ENABLE(CSS_REGIONS)
+    UNUSED_PARAM(parserContext);
+#endif
     return false;
 }
 
@@ -1064,6 +1060,9 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyBorderRightStyle:
     case CSSPropertyBorderTopStyle:
     case CSSPropertyBoxSizing:
+    case CSSPropertyBreakAfter:
+    case CSSPropertyBreakBefore:
+    case CSSPropertyBreakInside:
     case CSSPropertyCaptionSide:
     case CSSPropertyClear:
     case CSSPropertyDirection:
@@ -1074,6 +1073,7 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyImageRendering:
     case CSSPropertyListStylePosition:
     case CSSPropertyListStyleType:
+    case CSSPropertyObjectFit:
     case CSSPropertyOutlineStyle:
     case CSSPropertyOverflowWrap:
     case CSSPropertyOverflowX:
@@ -1098,7 +1098,8 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyVisibility:
     case CSSPropertyWebkitAppearance:
 #if ENABLE(CSS_COMPOSITING)
-    case CSSPropertyWebkitBlendMode:
+    case CSSPropertyMixBlendMode:
+    case CSSPropertyIsolation:
 #endif
     case CSSPropertyWebkitBackfaceVisibility:
     case CSSPropertyWebkitBorderAfterStyle:
@@ -1114,21 +1115,16 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyWebkitBoxLines:
     case CSSPropertyWebkitBoxOrient:
     case CSSPropertyWebkitBoxPack:
-    case CSSPropertyWebkitColorCorrection:
     case CSSPropertyWebkitColumnBreakAfter:
     case CSSPropertyWebkitColumnBreakBefore:
     case CSSPropertyWebkitColumnBreakInside:
-    case CSSPropertyWebkitColumnRuleStyle:
-    case CSSPropertyWebkitAlignContent:
-    case CSSPropertyWebkitAlignItems:
-    case CSSPropertyWebkitAlignSelf:
-    case CSSPropertyWebkitFlexDirection:
-    case CSSPropertyWebkitFlexWrap:
-    case CSSPropertyWebkitJustifyContent:
+    case CSSPropertyColumnFill:
+    case CSSPropertyColumnRuleStyle:
+    case CSSPropertyFlexDirection:
+    case CSSPropertyFlexWrap:
     case CSSPropertyWebkitFontKerning:
     case CSSPropertyWebkitFontSmoothing:
     case CSSPropertyWebkitHyphens:
-    case CSSPropertyWebkitGridAutoFlow:
     case CSSPropertyWebkitLineAlign:
     case CSSPropertyWebkitLineBreak:
     case CSSPropertyWebkitLineSnap:
@@ -1155,42 +1151,57 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyWebkitTextAlignLast:
 #endif // CSS3_TEXT
     case CSSPropertyWebkitTextCombine:
-    case CSSPropertyWebkitTextEmphasisPosition:
 #if ENABLE(CSS3_TEXT)
     case CSSPropertyWebkitTextJustify:
 #endif // CSS3_TEXT
     case CSSPropertyWebkitTextSecurity:
+    case CSSPropertyTransformStyle:
     case CSSPropertyWebkitTransformStyle:
     case CSSPropertyWebkitUserDrag:
     case CSSPropertyWebkitUserModify:
     case CSSPropertyWebkitUserSelect:
-#if ENABLE(CSS_EXCLUSIONS)
-    case CSSPropertyWebkitWrapFlow:
-    case CSSPropertyWebkitWrapThrough:
-#endif
     case CSSPropertyWebkitWritingMode:
     case CSSPropertyWhiteSpace:
     case CSSPropertyWordBreak:
     case CSSPropertyWordWrap:
+#if ENABLE(TOUCH_EVENTS)
+    case CSSPropertyTouchAction:
+#endif
+#if ENABLE(CSS_SCROLL_SNAP)
+    case CSSPropertyWebkitScrollSnapType:
+#endif
+#if ENABLE(CSS_TRAILING_WORD)
+    case CSSPropertyAppleTrailingWord:
+#endif
+    case CSSPropertyFontVariantPosition:
+    case CSSPropertyFontVariantCaps:
+    case CSSPropertyFontVariantAlternates:
         return true;
     default:
         return false;
     }
 }
 
-static bool parseKeywordValue(MutableStylePropertySet* declaration, CSSPropertyID propertyId, const String& string, bool important, const CSSParserContext& parserContext)
+static bool isUniversalKeyword(const String& string)
+{
+    // These keywords can be used for all properties.
+    return equalLettersIgnoringASCIICase(string, "initial")
+        || equalLettersIgnoringASCIICase(string, "inherit")
+        || equalLettersIgnoringASCIICase(string, "unset")
+        || equalLettersIgnoringASCIICase(string, "revert");
+}
+
+static CSSParser::ParseResult parseKeywordValue(MutableStyleProperties* declaration, CSSPropertyID propertyId, const String& string, bool important, const CSSParserContext& parserContext, StyleSheetContents* styleSheetContents)
 {
     ASSERT(!string.isEmpty());
 
     if (!isKeywordPropertyID(propertyId)) {
-        // All properties accept the values of "initial" and "inherit".
-        String lowerCaseString = string.lower();
-        if (lowerCaseString != "initial" && lowerCaseString != "inherit")
-            return false;
+        if (!isUniversalKeyword(string))
+            return CSSParser::ParseResult::Error;
 
-        // Parse initial/inherit shorthands using the CSSParser.
+        // Don't try to parse initial/inherit/unset/revert shorthands; return an error so the caller will use the full CSS parser.
         if (shorthandForProperty(propertyId).length())
-            return false;
+            return CSSParser::ParseResult::Error;
     }
 
     CSSParserString cssString;
@@ -1198,25 +1209,29 @@ static bool parseKeywordValue(MutableStylePropertySet* declaration, CSSPropertyI
     CSSValueID valueID = cssValueKeywordID(cssString);
 
     if (!valueID)
-        return false;
+        return CSSParser::ParseResult::Error;
 
     RefPtr<CSSValue> value;
     if (valueID == CSSValueInherit)
-        value = cssValuePool().createInheritedValue();
+        value = CSSValuePool::singleton().createInheritedValue();
     else if (valueID == CSSValueInitial)
-        value = cssValuePool().createExplicitInitialValue();
-    else if (isValidKeywordPropertyAndValue(propertyId, valueID, parserContext))
-        value = cssValuePool().createIdentifierValue(valueID);
+        value = CSSValuePool::singleton().createExplicitInitialValue();
+    else if (valueID == CSSValueUnset)
+        value = CSSValuePool::singleton().createUnsetValue();
+    else if (valueID == CSSValueRevert)
+        value = CSSValuePool::singleton().createRevertValue();
+    else if (isValidKeywordPropertyAndValue(propertyId, valueID, parserContext, styleSheetContents))
+        value = CSSValuePool::singleton().createIdentifierValue(valueID);
     else
-        return false;
+        return CSSParser::ParseResult::Error;
 
-    declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important));
-    return true;
+    return declaration->addParsedProperty(CSSProperty(propertyId, value.release(), important)) ? CSSParser::ParseResult::Changed : CSSParser::ParseResult::Unchanged;
 }
 
 template <typename CharacterType>
-static bool parseTransformArguments(WebKitCSSTransformValue* transformValue, CharacterType* characters, unsigned length, unsigned start, unsigned expectedCount)
+static bool parseTransformTranslateArguments(WebKitCSSTransformValue& transformValue, CharacterType* characters, unsigned length, unsigned start, unsigned expectedCount)
 {
+    auto& cssValuePool = CSSValuePool::singleton();
     while (expectedCount) {
         size_t end = WTF::find(characters, length, expectedCount == 1 ? ')' : ',', start);
         if (end == notFound || (expectedCount == 1 && end != length - 1))
@@ -1228,23 +1243,26 @@ static bool parseTransformArguments(WebKitCSSTransformValue* transformValue, Cha
             return false;
         if (unit != CSSPrimitiveValue::CSS_PX && (number || unit != CSSPrimitiveValue::CSS_NUMBER))
             return false;
-        transformValue->append(cssValuePool().createValue(number, unit));
+        transformValue.append(cssValuePool.createValue(number, CSSPrimitiveValue::CSS_PX));
         start = end + 1;
         --expectedCount;
     }
     return true;
 }
 
-static bool parseTranslateTransformValue(MutableStylePropertySet* properties, CSSPropertyID propertyID, const String& string, bool important)
+static CSSParser::ParseResult parseTranslateTransformValue(MutableStyleProperties* properties, CSSPropertyID propertyID, const String& string, bool important)
 {
-    if (propertyID != CSSPropertyWebkitTransform)
-        return false;
+    if (propertyID != CSSPropertyTransform)
+        return CSSParser::ParseResult::Error;
+
     static const unsigned shortestValidTransformStringLength = 12;
     static const unsigned likelyMultipartTransformStringLengthCutoff = 32;
     if (string.length() < shortestValidTransformStringLength || string.length() > likelyMultipartTransformStringLengthCutoff)
-        return false;
+        return CSSParser::ParseResult::Error;
+
     if (!string.startsWith("translate", false))
-        return false;
+        return CSSParser::ParseResult::Error;
+
     UChar c9 = toASCIILower(string[9]);
     UChar c10 = toASCIILower(string[10]);
 
@@ -1266,62 +1284,63 @@ static bool parseTranslateTransformValue(MutableStylePropertySet* properties, CS
         expectedArgumentCount = 3;
         argumentStart = 12;
     } else
-        return false;
+        return CSSParser::ParseResult::Error;
 
     RefPtr<WebKitCSSTransformValue> transformValue = WebKitCSSTransformValue::create(transformType);
     bool success;
     if (string.is8Bit())
-        success = parseTransformArguments(transformValue.get(), string.characters8(), string.length(), argumentStart, expectedArgumentCount);
+        success = parseTransformTranslateArguments(*transformValue, string.characters8(), string.length(), argumentStart, expectedArgumentCount);
     else
-        success = parseTransformArguments(transformValue.get(), string.characters16(), string.length(), argumentStart, expectedArgumentCount);
+        success = parseTransformTranslateArguments(*transformValue, string.characters16(), string.length(), argumentStart, expectedArgumentCount);
     if (!success)
-        return false;
+        return CSSParser::ParseResult::Error;
+
     RefPtr<CSSValueList> result = CSSValueList::createSpaceSeparated();
-    result->append(transformValue.release());
-    properties->addParsedProperty(CSSProperty(CSSPropertyWebkitTransform, result.release(), important));
-    return true;
+    result->append(transformValue.releaseNonNull());
+    return properties->addParsedProperty(CSSProperty(CSSPropertyTransform, result.release(), important)) ? CSSParser::ParseResult::Changed : CSSParser::ParseResult::Unchanged;
 }
 
-PassRefPtr<CSSValueList> CSSParser::parseFontFaceValue(const AtomicString& string)
+RefPtr<CSSValueList> CSSParser::parseFontFaceValue(const AtomicString& string)
 {
     if (string.isEmpty())
-        return 0;
-    RefPtr<MutableStylePropertySet> dummyStyle = MutableStylePropertySet::create();
-    if (!parseValue(dummyStyle.get(), CSSPropertyFontFamily, string, false, CSSQuirksMode, 0))
-        return 0;
+        return nullptr;
 
-    RefPtr<CSSValue> fontFamily = dummyStyle->getPropertyCSSValue(CSSPropertyFontFamily);
-    if (!fontFamily->isValueList())
-        return 0; // FIXME: "initial" and "inherit" should be parsed as font names in the face attribute.
-    return static_pointer_cast<CSSValueList>(fontFamily.release());
-}
+    Ref<CSSValueList> valueList = CSSValueList::createCommaSeparated();
 
-#if ENABLE(CSS_VARIABLES)
-bool CSSParser::parseValue(MutableStylePropertySet* declaration, CSSPropertyID propertyID, const String& string, bool important, Document* document)
-{
-    ASSERT(!string.isEmpty());
+    Vector<String> familyNames;
+    string.string().split(',', true, familyNames);
 
-    CSSParserContext context(document);
+    auto& cssValuePool = CSSValuePool::singleton();
+    for (auto& familyName : familyNames) {
+        String stripped = stripLeadingAndTrailingHTMLSpaces(familyName);
+        if (stripped.isEmpty())
+            return nullptr;
 
-    if (parseSimpleLengthValue(declaration, propertyID, string, important, context.mode))
-        return true;
-    if (parseColorValue(declaration, propertyID, string, important, context.mode))
-        return true;
-    if (parseKeywordValue(declaration, propertyID, string, important, context))
-        return true;
+        RefPtr<CSSValue> value;
+        for (auto propertyID : { CSSValueSerif, CSSValueSansSerif, CSSValueCursive, CSSValueFantasy, CSSValueMonospace, CSSValueWebkitBody }) {
+            if (equalIgnoringASCIICase(stripped, getValueName(propertyID))) {
+                value = cssValuePool.createIdentifierValue(propertyID);
+                break;
+            }
+        }
+        if (!value)
+            value = cssValuePool.createFontFamilyValue(stripped);
+        valueList->append(value.releaseNonNull());
+    }
 
-    CSSParser parser(context);
-    return parser.parseValue(declaration, propertyID, string, important, static_cast<StyleSheetContents*>(0));
+    return WTFMove(valueList);
 }
-#endif
 
-bool CSSParser::parseValue(MutableStylePropertySet* declaration, CSSPropertyID propertyID, const String& string, bool important, CSSParserMode cssParserMode, StyleSheetContents* contextStyleSheet)
+CSSParser::ParseResult CSSParser::parseValue(MutableStyleProperties* declaration, CSSPropertyID propertyID, const String& string, bool important, CSSParserMode cssParserMode, StyleSheetContents* contextStyleSheet)
 {
     ASSERT(!string.isEmpty());
-    if (parseSimpleLengthValue(declaration, propertyID, string, important, cssParserMode))
-        return true;
-    if (parseColorValue(declaration, propertyID, string, important, cssParserMode))
-        return true;
+    CSSParser::ParseResult result = parseSimpleLengthValue(declaration, propertyID, string, important, cssParserMode);
+    if (result != ParseResult::Error)
+        return result;
+
+    result = parseColorValue(declaration, propertyID, string, important, cssParserMode);
+    if (result != ParseResult::Error)
+        return result;
 
     CSSParserContext context(cssParserMode);
     if (contextStyleSheet) {
@@ -1329,16 +1348,32 @@ bool CSSParser::parseValue(MutableStylePropertySet* declaration, CSSPropertyID p
         context.mode = cssParserMode;
     }
 
-    if (parseKeywordValue(declaration, propertyID, string, important, context))
-        return true;
-    if (parseTranslateTransformValue(declaration, propertyID, string, important))
-        return true;
+    result = parseKeywordValue(declaration, propertyID, string, important, context, contextStyleSheet);
+    if (result != ParseResult::Error)
+        return result;
+
+    result = parseTranslateTransformValue(declaration, propertyID, string, important);
+    if (result != ParseResult::Error)
+        return result;
 
     CSSParser parser(context);
     return parser.parseValue(declaration, propertyID, string, important, contextStyleSheet);
 }
 
-bool CSSParser::parseValue(MutableStylePropertySet* declaration, CSSPropertyID propertyID, const String& string, bool important, StyleSheetContents* contextStyleSheet)
+CSSParser::ParseResult CSSParser::parseCustomPropertyValue(MutableStyleProperties* declaration, const AtomicString& propertyName, const String& string, bool important, CSSParserMode cssParserMode, StyleSheetContents* contextStyleSheet)
+{
+    CSSParserContext context(cssParserMode);
+    if (contextStyleSheet) {
+        context = contextStyleSheet->parserContext();
+        context.mode = cssParserMode;
+    }
+
+    CSSParser parser(context);
+    parser.setCustomPropertyName(propertyName);
+    return parser.parseValue(declaration, CSSPropertyCustom, string, important, contextStyleSheet);
+}
+
+CSSParser::ParseResult CSSParser::parseValue(MutableStyleProperties* declaration, CSSPropertyID propertyID, const String& string, bool important, StyleSheetContents* contextStyleSheet)
 {
     setStyleSheet(contextStyleSheet);
 
@@ -1349,24 +1384,25 @@ bool CSSParser::parseValue(MutableStylePropertySet* declaration, CSSPropertyID p
 
     cssyyparse(this);
 
-    m_rule = 0;
+    m_rule = nullptr;
+
+    ParseResult result = ParseResult::Error;
 
-    bool ok = false;
-    if (m_hasFontFaceOnlyValues)
-        deleteFontFaceOnlyValues();
     if (!m_parsedProperties.isEmpty()) {
-        ok = true;
-        declaration->addParsedProperties(m_parsedProperties);
+        result = declaration->addParsedProperties(m_parsedProperties) ? ParseResult::Changed : ParseResult::Unchanged;
         clearProperties();
     }
 
-    return ok;
+    return result;
 }
 
 // The color will only be changed when string contains a valid CSS color, so callers
 // can set it to a default color and ignore the boolean result.
 bool CSSParser::parseColor(RGBA32& color, const String& string, bool strict)
 {
+    if (string.isEmpty())
+        return false;
+
     // First try creating a color specified by name, rgba(), rgb() or "#" syntax.
     if (fastParseColor(color, string, strict))
         return true;
@@ -1377,15 +1413,15 @@ bool CSSParser::parseColor(RGBA32& color, const String& string, bool strict)
     if (!parser.parseColor(string))
         return false;
 
-    CSSValue* value = parser.m_parsedProperties.first().value();
-    if (!value->isPrimitiveValue())
+    CSSValue& value = *parser.m_parsedProperties.first().value();
+    if (!is<CSSPrimitiveValue>(value))
         return false;
 
-    CSSPrimitiveValue* primitiveValue = static_cast<CSSPrimitiveValue*>(value);
-    if (!primitiveValue->isRGBColor())
+    CSSPrimitiveValue& primitiveValue = downcast<CSSPrimitiveValue>(value);
+    if (!primitiveValue.isRGBColor())
         return false;
 
-    color = primitiveValue->getRGBA32Value();
+    color = primitiveValue.getRGBA32Value();
     return true;
 }
 
@@ -1393,7 +1429,7 @@ bool CSSParser::parseColor(const String& string)
 {
     setupParser("@-webkit-decls{color:", string, "} ");
     cssyyparse(this);
-    m_rule = 0;
+    m_rule = nullptr;
 
     return !m_parsedProperties.isEmpty() && m_parsedProperties.first().id() == CSSPropertyColor;
 }
@@ -1406,10 +1442,14 @@ bool CSSParser::parseSystemColor(RGBA32& color, const String& string, Document*
     CSSParserString cssColor;
     cssColor.init(string);
     CSSValueID id = cssValueKeywordID(cssColor);
-    if (id <= 0)
+    if (!validPrimitiveValueColor(id))
+        return false;
+
+    Color parsedColor = document->page()->theme().systemColor(id);
+    if (!parsedColor.isValid())
         return false;
 
-    color = document->page()->theme()->systemColor(id).rgb();
+    color = parsedColor.rgb();
     return true;
 }
 
@@ -1421,34 +1461,31 @@ void CSSParser::parseSelector(const String& string, CSSSelectorList& selectorLis
 
     cssyyparse(this);
 
-    m_selectorListForParseSelector = 0;
+    m_selectorListForParseSelector = nullptr;
 }
 
-PassRefPtr<ImmutableStylePropertySet> CSSParser::parseInlineStyleDeclaration(const String& string, Element* element)
+Ref<ImmutableStyleProperties> CSSParser::parseInlineStyleDeclaration(const String& string, Element* element)
 {
-    CSSParserContext context = element->document()->elementSheet()->contents()->parserContext();
-    context.mode = strictToCSSParserMode(element->isHTMLElement() && !element->document()->inQuirksMode());
-    return CSSParser(context).parseDeclaration(string, element->document()->elementSheet()->contents());
+    CSSParserContext context = element->document().elementSheet().contents().parserContext();
+    context.mode = strictToCSSParserMode(element->isHTMLElement() && !element->document().inQuirksMode());
+    return CSSParser(context).parseDeclaration(string, &element->document().elementSheet().contents());
 }
 
-PassRefPtr<ImmutableStylePropertySet> CSSParser::parseDeclaration(const String& string, StyleSheetContents* contextStyleSheet)
+Ref<ImmutableStyleProperties> CSSParser::parseDeclaration(const String& string, StyleSheetContents* contextStyleSheet)
 {
     setStyleSheet(contextStyleSheet);
 
     setupParser("@-webkit-decls{", string, "} ");
     cssyyparse(this);
-    m_rule = 0;
+    m_rule = nullptr;
 
-    if (m_hasFontFaceOnlyValues)
-        deleteFontFaceOnlyValues();
-
-    RefPtr<ImmutableStylePropertySet> style = createStylePropertySet();
+    Ref<ImmutableStyleProperties> style = createStyleProperties();
     clearProperties();
-    return style.release();
+    return style;
 }
 
 
-bool CSSParser::parseDeclaration(MutableStylePropertySet* declaration, const String& string, PassRefPtr<CSSRuleSourceData> prpRuleSourceData, StyleSheetContents* contextStyleSheet)
+bool CSSParser::parseDeclaration(MutableStyleProperties* declaration, const String& string, PassRefPtr<CSSRuleSourceData> prpRuleSourceData, StyleSheetContents* contextStyleSheet)
 {
     // Length of the "@-webkit-decls{" prefix.
     static const unsigned prefixLength = 15;
@@ -1457,17 +1494,15 @@ bool CSSParser::parseDeclaration(MutableStylePropertySet* declaration, const Str
 
     RefPtr<CSSRuleSourceData> ruleSourceData = prpRuleSourceData;
     if (ruleSourceData) {
-        m_currentRuleDataStack = adoptPtr(new RuleSourceDataList());
+        m_currentRuleDataStack = std::make_unique<RuleSourceDataList>();
         m_currentRuleDataStack->append(ruleSourceData);
     }
 
     setupParser("@-webkit-decls{", string, "} ");
     cssyyparse(this);
-    m_rule = 0;
+    m_rule = nullptr;
 
     bool ok = false;
-    if (m_hasFontFaceOnlyValues)
-        deleteFontFaceOnlyValues();
     if (!m_parsedProperties.isEmpty()) {
         ok = true;
         declaration->addParsedProperties(m_parsedProperties);
@@ -1485,13 +1520,13 @@ bool CSSParser::parseDeclaration(MutableStylePropertySet* declaration, const Str
         }
 
         fixUnparsedPropertyRanges(ruleSourceData.get());
-        m_currentRuleDataStack.clear();
+        m_currentRuleDataStack.reset();
     }
 
     return ok;
 }
 
-PassOwnPtr<MediaQuery> CSSParser::parseMediaQuery(const String& string)
+std::unique_ptr<MediaQuery> CSSParser::parseMediaQuery(const String& string)
 {
     if (string.isEmpty())
         return nullptr;
@@ -1503,57 +1538,101 @@ PassOwnPtr<MediaQuery> CSSParser::parseMediaQuery(const String& string)
     setupParser("@-webkit-mediaquery ", string, "} ");
     cssyyparse(this);
 
-    return m_mediaQuery.release();
+    return WTFMove(m_mediaQuery);
 }
 
-#if ENABLE(CSS_VARIABLES)
-static inline void filterProperties(bool important, const CSSParser::ParsedPropertyVector& input, Vector<CSSProperty, 256>& output, size_t& unusedEntries, BitArray<numCSSProperties>& seenProperties, HashSet<AtomicString>& seenVariables)
-#else
-static inline void filterProperties(bool important, const CSSParser::ParsedPropertyVector& input, Vector<CSSProperty, 256>& output, size_t& unusedEntries, BitArray<numCSSProperties>& seenProperties)
-#endif
+Vector<CSSParser::SourceSize> CSSParser::parseSizesAttribute(StringView string)
+{
+    Vector<SourceSize> result;
+
+    if (string.isEmpty())
+        return result;
+
+    ASSERT(!m_sourceSizeList);
+
+    setupParser("@-webkit-sizesattr ", string, "}");
+    cssyyparse(this);
+
+    if (!m_sourceSizeList)
+        return result;
+
+    result = WTFMove(*m_sourceSizeList);
+    m_sourceSizeList = nullptr;
+    return result;
+}
+
+// FIXME(141289): The following two constructors are only needed because of a bug in MSVC 2013 (and prior).
+// We should remove this code as soon as a Visual Studio update that fixes this problem is released.
+CSSParser::SourceSize::SourceSize(CSSParser::SourceSize&& original)
+    : expression(WTFMove(original.expression))
+    , length(original.length)
+{
+}
+
+CSSParser::SourceSize::SourceSize(std::unique_ptr<MediaQueryExp>&& origExp, RefPtr<CSSValue> value)
+    : expression(WTFMove(origExp))
+    , length(value)
+{
+}
+
+CSSParser::SourceSize CSSParser::sourceSize(std::unique_ptr<MediaQueryExp>&& expression, CSSParserValue& parserValue)
+{
+    RefPtr<CSSValue> value;
+    if (isCalculation(parserValue)) {
+        auto* args = parserValue.function->args.get();
+        if (args && args->size())
+            value = CSSCalcValue::create(parserValue.function->name, *args, CalculationRangeNonNegative);
+    }
+    if (!value)
+        value = parserValue.createCSSValue();
+    destroy(parserValue);
+    // FIXME: Calling the constructor explicitly here to work around an MSVC bug.
+    // For other compilers, we did not need to define the constructors and we could use aggregate initialization syntax.
+    return SourceSize(WTFMove(expression), WTFMove(value));
+}
+
+static inline void filterProperties(bool important, const CSSParser::ParsedPropertyVector& input, Vector<CSSProperty, 256>& output, size_t& unusedEntries, std::bitset<numCSSProperties>& seenProperties, HashSet<AtomicString>& seenCustomProperties)
 {
     // Add properties in reverse order so that highest priority definitions are reached first. Duplicate definitions can then be ignored when found.
     for (int i = input.size() - 1; i >= 0; --i) {
         const CSSProperty& property = input[i];
         if (property.isImportant() != important)
             continue;
-#if ENABLE(CSS_VARIABLES)
-        if (property.id() == CSSPropertyVariable) {
-            const AtomicString& name = static_cast<CSSVariableValue*>(property.value())->name();
-            if (seenVariables.contains(name))
-                continue;
-            seenVariables.add(name);
-            output[--unusedEntries] = property;
+        
+        if (property.id() == CSSPropertyCustom) {
+            if (property.value()) {
+                const AtomicString& name = downcast<CSSCustomPropertyValue>(*property.value()).name();
+                if (seenCustomProperties.contains(name))
+                    continue;
+                seenCustomProperties.add(name);
+                output[--unusedEntries] = property;
+            }
             continue;
         }
-#endif
+
         const unsigned propertyIDIndex = property.id() - firstCSSProperty;
-        if (seenProperties.get(propertyIDIndex))
+        ASSERT(propertyIDIndex < seenProperties.size());
+        if (seenProperties[propertyIDIndex])
             continue;
         seenProperties.set(propertyIDIndex);
         output[--unusedEntries] = property;
     }
 }
 
-PassRefPtr<ImmutableStylePropertySet> CSSParser::createStylePropertySet()
+Ref<ImmutableStyleProperties> CSSParser::createStyleProperties()
 {
-    BitArray<numCSSProperties> seenProperties;
+    std::bitset<numCSSProperties> seenProperties;
     size_t unusedEntries = m_parsedProperties.size();
     Vector<CSSProperty, 256> results(unusedEntries);
 
     // Important properties have higher priority, so add them first. Duplicate definitions can then be ignored when found.
-#if ENABLE(CSS_VARIABLES)
-    HashSet<AtomicString> seenVariables;
-    filterProperties(true, m_parsedProperties, results, unusedEntries, seenProperties, seenVariables);
-    filterProperties(false, m_parsedProperties, results, unusedEntries, seenProperties, seenVariables);
-#else
-    filterProperties(true, m_parsedProperties, results, unusedEntries, seenProperties);
-    filterProperties(false, m_parsedProperties, results, unusedEntries, seenProperties);
-#endif
+    HashSet<AtomicString> seenCustomProperties;
+    filterProperties(true, m_parsedProperties, results, unusedEntries, seenProperties, seenCustomProperties);
+    filterProperties(false, m_parsedProperties, results, unusedEntries, seenProperties, seenCustomProperties);
     if (unusedEntries)
         results.remove(0, unusedEntries);
 
-    return ImmutableStylePropertySet::create(results.data(), results.size(), m_context.mode);
+    return ImmutableStyleProperties::create(results.data(), results.size(), m_context.mode);
 }
 
 void CSSParser::addPropertyWithPrefixingVariant(CSSPropertyID propId, PassRefPtr<CSSValue> value, bool important, bool implicit)
@@ -1564,12 +1643,29 @@ void CSSParser::addPropertyWithPrefixingVariant(CSSPropertyID propId, PassRefPtr
     CSSPropertyID prefixingVariant = prefixingVariantForPropertyId(propId);
     if (prefixingVariant == propId)
         return;
-    addProperty(prefixingVariant, val.release(), important, implicit);
+
+    if (m_currentShorthand) {
+        // We can't use ShorthandScope here as we can already be inside one (e.g we are parsing CSSTransition).
+        m_currentShorthand = prefixingVariantForPropertyId(m_currentShorthand);
+        addProperty(prefixingVariant, val.release(), important, implicit);
+        m_currentShorthand = prefixingVariantForPropertyId(m_currentShorthand);
+    } else
+        addProperty(prefixingVariant, val.release(), important, implicit);
 }
 
 void CSSParser::addProperty(CSSPropertyID propId, PassRefPtr<CSSValue> value, bool important, bool implicit)
 {
-    m_parsedProperties.append(CSSProperty(propId, value, important, m_currentShorthand, m_implicitShorthand || implicit));
+    // This property doesn't belong to a shorthand or is a CSS variable (which will be resolved later).
+    if (!m_currentShorthand) {
+        m_parsedProperties.append(CSSProperty(propId, value, important, false, CSSPropertyInvalid, m_implicitShorthand || implicit));
+        return;
+    }
+
+    Vector<StylePropertyShorthand> shorthands = matchingShorthandsForLonghand(propId);
+    if (shorthands.size() == 1)
+        m_parsedProperties.append(CSSProperty(propId, value, important, true, CSSPropertyInvalid, m_implicitShorthand || implicit));
+    else
+        m_parsedProperties.append(CSSProperty(propId, value, important, true, indexOfShorthandForLonghand(m_currentShorthand, shorthands), m_implicitShorthand || implicit));
 }
 
 void CSSParser::rollbackLastProperties(int num)
@@ -1583,99 +1679,102 @@ void CSSParser::clearProperties()
 {
     m_parsedProperties.clear();
     m_numParsedPropertiesBeforeMarginBox = INVALID_NUM_PARSED_PROPERTIES;
-    m_hasFontFaceOnlyValues = false;
 }
 
-KURL CSSParser::completeURL(const CSSParserContext& context, const String& url)
+URL CSSParser::completeURL(const CSSParserContext& context, const String& url)
 {
     if (url.isNull())
-        return KURL();
+        return URL();
     if (context.charset.isEmpty())
-        return KURL(context.baseURL, url);
-    return KURL(context.baseURL, url, context.charset);
+        return URL(context.baseURL, url);
+    return URL(context.baseURL, url, context.charset);
 }
 
-KURL CSSParser::completeURL(const String& url) const
+URL CSSParser::completeURL(const String& url) const
 {
     return completeURL(m_context, url);
 }
 
-bool CSSParser::validCalculationUnit(CSSParserValue* value, Units unitflags, ReleaseParsedCalcValueCondition releaseCalc)
+bool CSSParser::validateCalculationUnit(ValueWithCalculation& valueWithCalculation, Units unitFlags)
 {
-    bool mustBeNonNegative = unitflags & FNonNeg;
+    bool mustBeNonNegative = unitFlags & FNonNeg;
 
-    if (!parseCalculation(value, mustBeNonNegative ? CalculationRangeNonNegative : CalculationRangeAll))
-        return false;
+    RefPtr<CSSCalcValue> calculation;
+    if (valueWithCalculation.calculation()) {
+        // The calculation value was already parsed so we reuse it. However, we may need to update its range.
+        calculation = valueWithCalculation.calculation();
+        calculation->setPermittedValueRange(mustBeNonNegative ? CalculationRangeNonNegative : CalculationRangeAll);
+    } else {
+        valueWithCalculation.setCalculation(parseCalculation(valueWithCalculation, mustBeNonNegative ? CalculationRangeNonNegative : CalculationRangeAll));
+        calculation = valueWithCalculation.calculation();
+        if (!calculation)
+            return false;
+    }
 
-    bool b = false;
-    switch (m_parsedCalculation->category()) {
+    bool isValid = false;
+    switch (calculation->category()) {
+    case CalcNumber:
+        isValid = (unitFlags & FNumber);
+        if (!isValid && (unitFlags & FInteger) && calculation->isInt())
+            isValid = true;
+        if (!isValid && (unitFlags & FPositiveInteger) && calculation->isInt() && calculation->isPositive())
+            isValid = true;
+        break;
     case CalcLength:
-        b = (unitflags & FLength);
+        isValid = (unitFlags & FLength);
         break;
     case CalcPercent:
-        b = (unitflags & FPercent);
-        if (b && mustBeNonNegative && m_parsedCalculation->isNegative())
-            b = false;
-        break;
-    case CalcNumber:
-        b = (unitflags & FNumber);
-        if (!b && (unitflags & FInteger) && m_parsedCalculation->isInt())
-            b = true;
-        if (b && mustBeNonNegative && m_parsedCalculation->isNegative())
-            b = false;
+        isValid = (unitFlags & FPercent);
         break;
     case CalcPercentLength:
-        b = (unitflags & FPercent) && (unitflags & FLength);
+        isValid = (unitFlags & FPercent) && (unitFlags & FLength);
         break;
     case CalcPercentNumber:
-        b = (unitflags & FPercent) && (unitflags & FNumber);
+        isValid = (unitFlags & FPercent) && (unitFlags & FNumber);
         break;
-#if ENABLE(CSS_VARIABLES)
-    case CalcVariable:
-        b = true;
+    case CalcAngle:
+        isValid = (unitFlags & FAngle);
+        break;
+    case CalcTime:
+        isValid = (unitFlags & FTime);
+        break;
+    case CalcFrequency:
+        isValid = (unitFlags & FFrequency);
         break;
-#endif
     case CalcOther:
         break;
     }
-    if (!b || releaseCalc == ReleaseParsedCalcValue)
-        m_parsedCalculation.release();
-    return b;    
+
+    return isValid;
 }
 
-inline bool CSSParser::shouldAcceptUnitLessValues(CSSParserValue* value, Units unitflags, CSSParserMode cssParserMode)
+inline bool CSSParser::shouldAcceptUnitLessValues(CSSParserValue& value, Units unitFlags, CSSParserMode cssParserMode)
 {
     // Qirks mode and svg presentation attributes accept unit less values.
-    return (unitflags & (FLength | FAngle | FTime)) && (!value->fValue || cssParserMode == CSSQuirksMode || cssParserMode == SVGAttributeMode);
+    return (unitFlags & (FLength | FAngle | FTime)) && (!value.fValue || cssParserMode == CSSQuirksMode || cssParserMode == SVGAttributeMode);
 }
 
-bool CSSParser::validUnit(CSSParserValue* value, Units unitflags, CSSParserMode cssParserMode, ReleaseParsedCalcValueCondition releaseCalc)
+bool CSSParser::validateUnit(ValueWithCalculation& valueWithCalculation, Units unitFlags, CSSParserMode cssParserMode)
 {
-    if (isCalculation(value))
-        return validCalculationUnit(value, unitflags, releaseCalc);
+    if (isCalculation(valueWithCalculation))
+        return validateCalculationUnit(valueWithCalculation, unitFlags);
         
     bool b = false;
-    switch (value->unit) {
-#if ENABLE(CSS_VARIABLES)
-    case CSSPrimitiveValue::CSS_VARIABLE_NAME:
-        // Variables are checked at the point they are dereferenced because unit type is not available here.
-        b = true;
-        break;
-#endif
+    switch (valueWithCalculation.value().unit) {
     case CSSPrimitiveValue::CSS_NUMBER:
-        b = (unitflags & FNumber);
-        if (!b && shouldAcceptUnitLessValues(value, unitflags, cssParserMode)) {
-            value->unit = (unitflags & FLength) ? CSSPrimitiveValue::CSS_PX :
-                          ((unitflags & FAngle) ? CSSPrimitiveValue::CSS_DEG : CSSPrimitiveValue::CSS_MS);
+        b = (unitFlags & FNumber);
+        if (!b && shouldAcceptUnitLessValues(valueWithCalculation, unitFlags, cssParserMode)) {
+            valueWithCalculation.value().unit = (unitFlags & FLength) ? CSSPrimitiveValue::CSS_PX :
+                          ((unitFlags & FAngle) ? CSSPrimitiveValue::CSS_DEG : CSSPrimitiveValue::CSS_MS);
             b = true;
         }
-        if (!b && (unitflags & FInteger) && value->isInt)
+        if (!b && (unitFlags & FInteger) && valueWithCalculation.value().isInt)
             b = true;
-        if (!b && (unitflags & FPositiveInteger) && value->isInt && value->fValue > 0)
+        if (!b && (unitFlags & FPositiveInteger) && valueWithCalculation.value().isInt && valueWithCalculation.value().fValue > 0)
             b = true;
         break;
     case CSSPrimitiveValue::CSS_PERCENTAGE:
-        b = (unitflags & FPercent);
+        b = (unitFlags & FPercent);
         break;
     case CSSParserValue::Q_EMS:
     case CSSPrimitiveValue::CSS_EMS:
@@ -1692,23 +1791,23 @@ bool CSSParser::validUnit(CSSParserValue* value, Units unitflags, CSSParserMode
     case CSSPrimitiveValue::CSS_VH:
     case CSSPrimitiveValue::CSS_VMIN:
     case CSSPrimitiveValue::CSS_VMAX:
-        b = (unitflags & FLength);
+        b = (unitFlags & FLength);
         break;
     case CSSPrimitiveValue::CSS_MS:
     case CSSPrimitiveValue::CSS_S:
-        b = (unitflags & FTime);
+        b = (unitFlags & FTime);
         break;
     case CSSPrimitiveValue::CSS_DEG:
     case CSSPrimitiveValue::CSS_RAD:
     case CSSPrimitiveValue::CSS_GRAD:
     case CSSPrimitiveValue::CSS_TURN:
-        b = (unitflags & FAngle);
+        b = (unitFlags & FAngle);
         break;
 #if ENABLE(CSS_IMAGE_RESOLUTION) || ENABLE(RESOLUTION_MEDIA_QUERY)
     case CSSPrimitiveValue::CSS_DPPX:
     case CSSPrimitiveValue::CSS_DPI:
     case CSSPrimitiveValue::CSS_DPCM:
-        b = (unitflags & FResolution);
+        b = (unitFlags & FResolution);
         break;
 #endif
     case CSSPrimitiveValue::CSS_HZ:
@@ -1717,104 +1816,79 @@ bool CSSParser::validUnit(CSSParserValue* value, Units unitflags, CSSParserMode
     default:
         break;
     }
-    if (b && unitflags & FNonNeg && value->fValue < 0)
+    if (b && unitFlags & FNonNeg && valueWithCalculation.value().fValue < 0)
+        b = false;
+    if (b && std::isinf(valueWithCalculation.value().fValue))
         b = false;
     return b;
 }
 
-inline PassRefPtr<CSSPrimitiveValue> CSSParser::createPrimitiveNumericValue(CSSParserValue* value)
+inline Ref<CSSPrimitiveValue> CSSParser::createPrimitiveNumericValue(ValueWithCalculation& valueWithCalculation)
 {
-#if ENABLE(CSS_VARIABLES)
-    if (value->unit == CSSPrimitiveValue::CSS_VARIABLE_NAME)
-        return createPrimitiveVariableNameValue(value);
-#endif
-
-    if (m_parsedCalculation) {
-        ASSERT(isCalculation(value));
-        return CSSPrimitiveValue::create(m_parsedCalculation.release());
-    }
+    if (valueWithCalculation.calculation())
+        return CSSPrimitiveValue::create(valueWithCalculation.calculation());
 
+    CSSParserValue& value = valueWithCalculation;
 #if ENABLE(CSS_IMAGE_RESOLUTION) || ENABLE(RESOLUTION_MEDIA_QUERY)
-    ASSERT((value->unit >= CSSPrimitiveValue::CSS_NUMBER && value->unit <= CSSPrimitiveValue::CSS_KHZ)
-        || (value->unit >= CSSPrimitiveValue::CSS_TURN && value->unit <= CSSPrimitiveValue::CSS_CHS)
-        || (value->unit >= CSSPrimitiveValue::CSS_VW && value->unit <= CSSPrimitiveValue::CSS_VMAX)
-        || (value->unit >= CSSPrimitiveValue::CSS_DPPX && value->unit <= CSSPrimitiveValue::CSS_DPCM));
+    ASSERT((value.unit >= CSSPrimitiveValue::CSS_NUMBER && value.unit <= CSSPrimitiveValue::CSS_KHZ)
+        || (value.unit >= CSSPrimitiveValue::CSS_TURN && value.unit <= CSSPrimitiveValue::CSS_CHS)
+        || (value.unit >= CSSPrimitiveValue::CSS_VW && value.unit <= CSSPrimitiveValue::CSS_VMAX)
+        || (value.unit >= CSSPrimitiveValue::CSS_DPPX && value.unit <= CSSPrimitiveValue::CSS_DPCM));
 #else
-    ASSERT((value->unit >= CSSPrimitiveValue::CSS_NUMBER && value->unit <= CSSPrimitiveValue::CSS_KHZ)
-        || (value->unit >= CSSPrimitiveValue::CSS_TURN && value->unit <= CSSPrimitiveValue::CSS_CHS)
-        || (value->unit >= CSSPrimitiveValue::CSS_VW && value->unit <= CSSPrimitiveValue::CSS_VMAX));
+    ASSERT((value.unit >= CSSPrimitiveValue::CSS_NUMBER && value.unit <= CSSPrimitiveValue::CSS_KHZ)
+        || (value.unit >= CSSPrimitiveValue::CSS_TURN && value.unit <= CSSPrimitiveValue::CSS_CHS)
+        || (value.unit >= CSSPrimitiveValue::CSS_VW && value.unit <= CSSPrimitiveValue::CSS_VMAX));
 #endif
-    return cssValuePool().createValue(value->fValue, static_cast<CSSPrimitiveValue::UnitTypes>(value->unit));
-}
-
-inline PassRefPtr<CSSPrimitiveValue> CSSParser::createPrimitiveStringValue(CSSParserValue* value)
-{
-    ASSERT(value->unit == CSSPrimitiveValue::CSS_STRING || value->unit == CSSPrimitiveValue::CSS_IDENT);
-    return cssValuePool().createValue(value->string, CSSPrimitiveValue::CSS_STRING);
+    return CSSValuePool::singleton().createValue(value.fValue, static_cast<CSSPrimitiveValue::UnitTypes>(value.unit));
 }
 
-#if ENABLE(CSS_VARIABLES)
-inline PassRefPtr<CSSPrimitiveValue> CSSParser::createPrimitiveVariableNameValue(CSSParserValue* value)
+inline Ref<CSSPrimitiveValue> CSSParser::createPrimitiveStringValue(CSSParserValue& value)
 {
-    ASSERT(value->unit == CSSPrimitiveValue::CSS_VARIABLE_NAME);
-    return CSSPrimitiveValue::create(value->string, CSSPrimitiveValue::CSS_VARIABLE_NAME);
+    ASSERT(value.unit == CSSPrimitiveValue::CSS_STRING || value.unit == CSSPrimitiveValue::CSS_IDENT);
+    return CSSValuePool::singleton().createValue(value.string, CSSPrimitiveValue::CSS_STRING);
 }
-#endif
 
 static inline bool isComma(CSSParserValue* value)
 { 
     return value && value->unit == CSSParserValue::Operator && value->iValue == ','; 
 }
 
-static inline bool isForwardSlashOperator(CSSParserValue* value)
+static inline bool isForwardSlashOperator(CSSParserValue& value)
 {
-    ASSERT(value);
-    return value->unit == CSSParserValue::Operator && value->iValue == '/';
+    return value.unit == CSSParserValue::Operator && value.iValue == '/';
 }
 
-bool CSSParser::validWidth(CSSParserValue* value)
+bool CSSParser::isValidSize(ValueWithCalculation& valueWithCalculation)
 {
-    int id = value->id;
+    int id = valueWithCalculation.value().id;
     if (id == CSSValueIntrinsic || id == CSSValueMinIntrinsic || id == CSSValueWebkitMinContent || id == CSSValueWebkitMaxContent || id == CSSValueWebkitFillAvailable || id == CSSValueWebkitFitContent)
         return true;
-    return !id && validUnit(value, FLength | FPercent | FNonNeg);
-}
-
-// FIXME: Combine this with validWidth when we support fit-content, et al, for heights.
-bool CSSParser::validHeight(CSSParserValue* value)
-{
-    int id = value->id;
-    if (id == CSSValueIntrinsic || id == CSSValueMinIntrinsic)
-        return true;
-    return !id && validUnit(value, FLength | FPercent | FNonNeg);
+    return !id && validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg);
 }
 
-inline PassRefPtr<CSSPrimitiveValue> CSSParser::parseValidPrimitive(CSSValueID identifier, CSSParserValue* value)
+inline RefPtr<CSSPrimitiveValue> CSSParser::parseValidPrimitive(CSSValueID identifier, ValueWithCalculation& valueWithCalculation)
 {
     if (identifier)
-        return cssValuePool().createIdentifierValue(identifier);
-    if (value->unit == CSSPrimitiveValue::CSS_STRING)
-        return createPrimitiveStringValue(value);
-    if (value->unit >= CSSPrimitiveValue::CSS_NUMBER && value->unit <= CSSPrimitiveValue::CSS_KHZ)
-        return createPrimitiveNumericValue(value);
-    if (value->unit >= CSSPrimitiveValue::CSS_TURN && value->unit <= CSSPrimitiveValue::CSS_CHS)
-        return createPrimitiveNumericValue(value);
-    if (value->unit >= CSSPrimitiveValue::CSS_VW && value->unit <= CSSPrimitiveValue::CSS_VMAX)
-        return createPrimitiveNumericValue(value);
+        return CSSValuePool::singleton().createIdentifierValue(identifier);
+
+    if (valueWithCalculation.value().unit == CSSPrimitiveValue::CSS_STRING)
+        return createPrimitiveStringValue(valueWithCalculation);
+    if (valueWithCalculation.value().unit >= CSSPrimitiveValue::CSS_NUMBER && valueWithCalculation.value().unit <= CSSPrimitiveValue::CSS_KHZ)
+        return createPrimitiveNumericValue(valueWithCalculation);
+    if (valueWithCalculation.value().unit >= CSSPrimitiveValue::CSS_TURN && valueWithCalculation.value().unit <= CSSPrimitiveValue::CSS_CHS)
+        return createPrimitiveNumericValue(valueWithCalculation);
+    if (valueWithCalculation.value().unit >= CSSPrimitiveValue::CSS_VW && valueWithCalculation.value().unit <= CSSPrimitiveValue::CSS_VMAX)
+        return createPrimitiveNumericValue(valueWithCalculation);
 #if ENABLE(CSS_IMAGE_RESOLUTION) || ENABLE(RESOLUTION_MEDIA_QUERY)
-    if (value->unit >= CSSPrimitiveValue::CSS_DPPX && value->unit <= CSSPrimitiveValue::CSS_DPCM)
-        return createPrimitiveNumericValue(value);
-#endif
-#if ENABLE(CSS_VARIABLES)
-    if (value->unit == CSSPrimitiveValue::CSS_VARIABLE_NAME)
-        return createPrimitiveVariableNameValue(value);
+    if (valueWithCalculation.value().unit >= CSSPrimitiveValue::CSS_DPPX && valueWithCalculation.value().unit <= CSSPrimitiveValue::CSS_DPCM)
+        return createPrimitiveNumericValue(valueWithCalculation);
 #endif
-    if (value->unit >= CSSParserValue::Q_EMS)
-        return CSSPrimitiveValue::createAllowingMarginQuirk(value->fValue, CSSPrimitiveValue::CSS_EMS);
-    if (isCalculation(value))
-        return CSSPrimitiveValue::create(m_parsedCalculation.release());
+    if (valueWithCalculation.value().unit >= CSSParserValue::Q_EMS)
+        return CSSPrimitiveValue::createAllowingMarginQuirk(valueWithCalculation.value().fValue, CSSPrimitiveValue::CSS_EMS);
+    if (valueWithCalculation.calculation())
+        return CSSPrimitiveValue::create(valueWithCalculation.calculation());
 
-    return 0;
+    return nullptr;
 }
 
 void CSSParser::addExpandedPropertyForValue(CSSPropertyID propId, PassRefPtr<CSSValue> prpValue, bool important)
@@ -1833,52 +1907,73 @@ void CSSParser::addExpandedPropertyForValue(CSSPropertyID propId, PassRefPtr<CSS
         addProperty(longhands[i], value, important);
 }
 
-bool CSSParser::parseValue(CSSPropertyID propId, bool important)
+RefPtr<CSSValue> CSSParser::parseVariableDependentValue(CSSPropertyID propID, const CSSVariableDependentValue& dependentValue, const CustomPropertyValueMap& customProperties)
 {
-    if (!m_valueList)
-        return false;
-
-    CSSParserValue* value = m_valueList->current();
+    m_valueList.reset(new CSSParserValueList());
+    if (!dependentValue.valueList()->buildParserValueListSubstitutingVariables(m_valueList.get(), customProperties))
+        return nullptr;
+    bool parsed = parseValue(dependentValue.propertyID(), false);
+    if (!parsed)
+        return nullptr;
+    for (size_t i = 0; i < m_parsedProperties.size(); ++i) {
+        if (m_parsedProperties[i].id() == propID)
+            return m_parsedProperties[i].value();
+    }
+    return nullptr;
+}
 
-    if (!value)
+bool CSSParser::parseValue(CSSPropertyID propId, bool important)
+{
+    if (!m_valueList || !m_valueList->current())
         return false;
-
-    // Note: m_parsedCalculation is used to pass the calc value to validUnit and then cleared at the end of this function.
-    // FIXME: This is to avoid having to pass parsedCalc to all validUnit callers.
-    ASSERT(!m_parsedCalculation);
     
-    CSSValueID id = value->id;
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    CSSValueID id = valueWithCalculation.value().id;
+    
+    if (propId == CSSPropertyCustom)
+        return parseCustomPropertyDeclaration(important, id);
 
-    int num = inShorthand() ? 1 : m_valueList->size();
+    if (m_valueList->containsVariables()) {
+        RefPtr<CSSValueList> valueList = CSSValueList::createFromParserValueList(*m_valueList);
+        addExpandedPropertyForValue(propId, CSSVariableDependentValue::create(valueList, propId), important);
+        return true;
+    }
+
+    auto& cssValuePool = CSSValuePool::singleton();
+    unsigned num = inShorthand() ? 1 : m_valueList->size();
 
     if (id == CSSValueInherit) {
         if (num != 1)
             return false;
-        addExpandedPropertyForValue(propId, cssValuePool().createInheritedValue(), important);
+        addExpandedPropertyForValue(propId, cssValuePool.createInheritedValue(), important);
         return true;
     }
     else if (id == CSSValueInitial) {
         if (num != 1)
             return false;
-        addExpandedPropertyForValue(propId, cssValuePool().createExplicitInitialValue(), important);
+        addExpandedPropertyForValue(propId, cssValuePool.createExplicitInitialValue(), important);
         return true;
-    }
-
-#if ENABLE(CSS_VARIABLES)
-    if (!id && value->unit == CSSPrimitiveValue::CSS_VARIABLE_NAME && num == 1) {
-        addProperty(propId, createPrimitiveVariableNameValue(value), important);
-        m_valueList->next();
+    } else if (id == CSSValueUnset) {
+        if (num != 1)
+            return false;
+        addExpandedPropertyForValue(propId, cssValuePool.createUnsetValue(), important);
+        return true;
+    } else if (id == CSSValueRevert) {
+        if (num != 1)
+            return false;
+        addExpandedPropertyForValue(propId, cssValuePool.createRevertValue(), important);
         return true;
     }
-    ASSERT(propId != CSSPropertyVariable);
-#endif
+    
+    if (propId == CSSPropertyAll)
+        return false; // "all" doesn't allow you to specify anything other than inherit/initial/unset.
 
     if (isKeywordPropertyID(propId)) {
-        if (!isValidKeywordPropertyAndValue(propId, id, m_context))
+        if (!isValidKeywordPropertyAndValue(propId, id, m_context, m_styleSheet))
             return false;
         if (m_valueList->next() && !inShorthand())
             return false;
-        addProperty(propId, cssValuePool().createIdentifierValue(id), important);
+        addProperty(propId, cssValuePool.createIdentifierValue(id), important);
         return true;
     }
 
@@ -1895,7 +1990,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         return parseSize(propId, important);
 
     case CSSPropertyQuotes:               // [<string> <string>]+ | none | inherit
-        if (id)
+        if (id == CSSValueNone)
             validPrimitive = true;
         else
             return parseQuotes(propId, important);
@@ -1914,10 +2009,13 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         // close-quote | no-open-quote | no-close-quote ]+ | inherit
         return parseContent(propId, important);
 
+    case CSSPropertyAlt: // [ <string> | attr(X) ]
+        return parseAlt(propId, important);
+            
     case CSSPropertyClip:                 // <shape> | auto | inherit
         if (id == CSSValueAuto)
             validPrimitive = true;
-        else if (value->unit == CSSParserValue::Function)
+        else if (valueWithCalculation.value().unit == CSSParserValue::Function)
             return parseClipShape(propId, important);
         break;
 
@@ -1936,7 +2034,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         // pagination controls, it should default to hidden. If the overflow-y value is anything but
         // paged-x or paged-y, then overflow-x and overflow-y should have the same value.
         if (id == CSSValueWebkitPagedX || id == CSSValueWebkitPagedY)
-            overflowXValue = cssValuePool().createIdentifierValue(CSSValueAuto);
+            overflowXValue = cssValuePool.createIdentifierValue(CSSValueAuto);
         else
             overflowXValue = m_parsedProperties.last().value();
         addProperty(CSSPropertyOverflowX, overflowXValue.release(), important);
@@ -1956,6 +2054,10 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             return false;
         return parseFontWeight(important);
     }
+
+    case CSSPropertyFontSynthesis: // none | [ weight || style ]
+        return parseFontSynthesis(important);
+
     case CSSPropertyBorderSpacing: {
         if (num == 1) {
             ShorthandScope scope(this, CSSPropertyBorderSpacing);
@@ -1975,7 +2077,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     }
     case CSSPropertyWebkitBorderHorizontalSpacing:
     case CSSPropertyWebkitBorderVerticalSpacing:
-        validPrimitive = validUnit(value, FLength | FNonNeg);
+        validPrimitive = validateUnit(valueWithCalculation, FLength | FNonNeg);
         break;
     case CSSPropertyOutlineColor:        // <color> | invert | inherit
         // Outline color has "invert" as additional keyword.
@@ -1984,7 +2086,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             validPrimitive = true;
             break;
         }
-        /* nobreak */
+        FALLTHROUGH;
     case CSSPropertyBackgroundColor: // <color> | inherit
     case CSSPropertyBorderTopColor: // <color> | inherit
     case CSSPropertyBorderRightColor:
@@ -1998,10 +2100,8 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyTextLineThroughColor: // CSS3 text decoration colors
     case CSSPropertyTextUnderlineColor:
     case CSSPropertyTextOverlineColor:
-    case CSSPropertyWebkitColumnRuleColor:
-#if ENABLE(CSS3_TEXT)
+    case CSSPropertyColumnRuleColor:
     case CSSPropertyWebkitTextDecorationColor:
-#endif // CSS3_TEXT
     case CSSPropertyWebkitTextEmphasisColor:
     case CSSPropertyWebkitTextFillColor:
     case CSSPropertyWebkitTextStrokeColor:
@@ -2010,8 +2110,8 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
                                     // since we use this in our UA sheets.
         else if (id == CSSValueCurrentcolor)
             validPrimitive = true;
-        else if ((id >= CSSValueAqua && id <= CSSValueWindowtext) || id == CSSValueMenu ||
-             (id >= CSSValueWebkitFocusRingColor && id < CSSValueWebkitText && inQuirksMode())) {
+        else if (isValidSystemColorValue(id) || id == CSSValueMenu
+            || (id >= CSSValueWebkitFocusRingColor && id < CSSValueWebkitText && inQuirksMode())) {
             validPrimitive = true;
         } else {
             parsedValue = parseColor();
@@ -2026,17 +2126,19 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         // [ auto | crosshair | default | pointer | progress | move | e-resize | ne-resize |
         // nw-resize | n-resize | se-resize | sw-resize | s-resize | w-resize | ew-resize |
         // ns-resize | nesw-resize | nwse-resize | col-resize | row-resize | text | wait | help |
-        // vertical-text | cell | context-menu | alias | copy | no-drop | not-allowed | -webkit-zoom-in
-        // -webkit-zoom-out | all-scroll | -webkit-grab | -webkit-grabbing ] ] | inherit
+        // vertical-text | cell | context-menu | alias | copy | no-drop | not-allowed |
+        // zoom-in | zoom-out | all-scroll | -webkit-grab | -webkit-grabbing | -webkit-zoom-in |
+        // -webkit-zoom-out ] ] | inherit
         RefPtr<CSSValueList> list;
+        CSSParserValue* value = &valueWithCalculation.value();
         while (value) {
-            RefPtr<CSSValue> image = 0;
+            RefPtr<CSSValue> image;
             if (value->unit == CSSPrimitiveValue::CSS_URI) {
                 String uri = value->string;
                 if (!uri.isNull())
                     image = CSSImageValue::create(completeURL(uri));
 #if ENABLE(CSS_IMAGE_SET) && ENABLE(MOUSE_CURSOR_SCALE)
-            } else if (value->unit == CSSParserValue::Function && equalIgnoringCase(value->function->name, "-webkit-image-set(")) {
+            } else if (value->unit == CSSParserValue::Function && equalLettersIgnoringASCIICase(value->function->name, "-webkit-image-set(")) {
                 image = parseImageSet();
                 if (!image)
                     break;
@@ -2064,29 +2166,31 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
                 list = CSSValueList::createCommaSeparated();
 
             if (image)
-                list->append(CSSCursorImageValue::create(image, hasHotSpot, hotSpot));
+                list->append(CSSCursorImageValue::create(image.releaseNonNull(), hasHotSpot, hotSpot));
 
             if ((inStrictMode() && !value) || (value && !(value->unit == CSSParserValue::Operator && value->iValue == ',')))
                 return false;
             value = m_valueList->next(); // comma
         }
         if (list) {
-            if (!value) { // no value after url list (MSIE 5 compatibility)
+            if (!value) {
+                // no value after url list (MSIE 5 compatibility)
                 if (list->length() != 1)
                     return false;
             } else if (inQuirksMode() && value->id == CSSValueHand) // MSIE 5 compatibility :/
-                list->append(cssValuePool().createIdentifierValue(CSSValuePointer));
-            else if ((value->id >= CSSValueAuto && value->id <= CSSValueWebkitGrabbing) || value->id == CSSValueCopy || value->id == CSSValueNone)
-                list->append(cssValuePool().createIdentifierValue(value->id));
+                list->append(cssValuePool.createIdentifierValue(CSSValuePointer));
+            else if ((value->id >= CSSValueAuto && value->id <= CSSValueWebkitZoomOut) || value->id == CSSValueCopy || value->id == CSSValueNone)
+                list->append(cssValuePool.createIdentifierValue(value->id));
             m_valueList->next();
             parsedValue = list.release();
             break;
         } else if (value) {
             id = value->id;
-            if (inQuirksMode() && value->id == CSSValueHand) { // MSIE 5 compatibility :/
+            if (inQuirksMode() && value->id == CSSValueHand) {
+                // MSIE 5 compatibility :/
                 id = CSSValuePointer;
                 validPrimitive = true;
-            } else if ((value->id >= CSSValueAuto && value->id <= CSSValueWebkitGrabbing) || value->id == CSSValueCopy || value->id == CSSValueNone)
+            } else if ((value->id >= CSSValueAuto && value->id <= CSSValueWebkitZoomOut) || value->id == CSSValueCopy || value->id == CSSValueNone)
                 validPrimitive = true;
         } else {
             ASSERT_NOT_REACHED();
@@ -2103,7 +2207,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
 #endif
 
     case CSSPropertyBackgroundAttachment:
-    case CSSPropertyWebkitBackgroundBlendMode:
+    case CSSPropertyBackgroundBlendMode:
     case CSSPropertyBackgroundClip:
     case CSSPropertyWebkitBackgroundClip:
     case CSSPropertyWebkitBackgroundComposite:
@@ -2126,6 +2230,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitMaskPositionX:
     case CSSPropertyWebkitMaskPositionY:
     case CSSPropertyWebkitMaskSize:
+    case CSSPropertyWebkitMaskSourceType:
     case CSSPropertyWebkitMaskRepeat:
     case CSSPropertyWebkitMaskRepeatX:
     case CSSPropertyWebkitMaskRepeatY:
@@ -2135,12 +2240,12 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         CSSPropertyID propId1, propId2;
         bool result = false;
         if (parseFillProperty(propId, propId1, propId2, val1, val2)) {
-            OwnPtr<ShorthandScope> shorthandScope;
+            std::unique_ptr<ShorthandScope> shorthandScope;
             if (propId == CSSPropertyBackgroundPosition ||
                 propId == CSSPropertyBackgroundRepeat ||
                 propId == CSSPropertyWebkitMaskPosition ||
                 propId == CSSPropertyWebkitMaskRepeat) {
-                shorthandScope = adoptPtr(new ShorthandScope(this, propId));
+                shorthandScope = std::make_unique<ShorthandScope>(this, propId);
             }
             addProperty(propId1, val1.release(), important);
             if (val2)
@@ -2154,19 +2259,19 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyBorderImageSource:
     case CSSPropertyWebkitMaskBoxImageSource:
         if (id == CSSValueNone) {
-            parsedValue = cssValuePool().createIdentifierValue(CSSValueNone);
+            parsedValue = cssValuePool.createIdentifierValue(CSSValueNone);
             m_valueList->next();
-        } else if (value->unit == CSSPrimitiveValue::CSS_URI) {
-            parsedValue = CSSImageValue::create(completeURL(value->string));
+        } else if (valueWithCalculation.value().unit == CSSPrimitiveValue::CSS_URI) {
+            parsedValue = CSSImageValue::create(completeURL(valueWithCalculation.value().string));
             m_valueList->next();
-        } else if (isGeneratedImageValue(value)) {
-            if (parseGeneratedImage(m_valueList.get(), parsedValue))
+        } else if (isGeneratedImageValue(valueWithCalculation)) {
+            if (parseGeneratedImage(*m_valueList, parsedValue))
                 m_valueList->next();
             else
                 return false;
         }
 #if ENABLE(CSS_IMAGE_SET)
-        else if (value->unit == CSSParserValue::Function && equalIgnoringCase(value->function->name, "-webkit-image-set(")) {
+        else if (valueWithCalculation.value().unit == CSSParserValue::Function && equalLettersIgnoringASCIICase(valueWithCalculation.value().function->name, "-webkit-image-set(")) {
             parsedValue = parseImageSet();
             if (!parsedValue)
                 return false;
@@ -2185,19 +2290,25 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitBorderEndWidth:
     case CSSPropertyWebkitBorderBeforeWidth:
     case CSSPropertyWebkitBorderAfterWidth:
-    case CSSPropertyWebkitColumnRuleWidth:
+    case CSSPropertyColumnRuleWidth:
         if (id == CSSValueThin || id == CSSValueMedium || id == CSSValueThick)
             validPrimitive = true;
         else
-            validPrimitive = validUnit(value, FLength | FNonNeg);
+            validPrimitive = validateUnit(valueWithCalculation, FLength | FNonNeg);
         break;
 
     case CSSPropertyLetterSpacing:       // normal | <length> | inherit
-    case CSSPropertyWordSpacing:         // normal | <length> | inherit
         if (id == CSSValueNormal)
             validPrimitive = true;
         else
-            validPrimitive = validUnit(value, FLength);
+            validPrimitive = validateUnit(valueWithCalculation, FLength);
+        break;
+
+    case CSSPropertyWordSpacing:         // normal | <length> | <percentage> | inherit
+        if (id == CSSValueNormal)
+            validPrimitive = true;
+        else
+            validPrimitive = validateUnit(valueWithCalculation, FLength | FPercent);
         break;
 
     case CSSPropertyTextIndent:
@@ -2212,45 +2323,33 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitPaddingEnd:
     case CSSPropertyWebkitPaddingBefore:
     case CSSPropertyWebkitPaddingAfter:
-        validPrimitive = (!id && validUnit(value, FLength | FPercent | FNonNeg));
+        validPrimitive = (!id && validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg));
         break;
 
     case CSSPropertyMaxWidth:
     case CSSPropertyWebkitMaxLogicalWidth:
-        validPrimitive = (id == CSSValueNone || validWidth(value));
-        break;
-
-    case CSSPropertyMinWidth:
-    case CSSPropertyWebkitMinLogicalWidth:
-        validPrimitive = validWidth(value);
-        break;
-
-    case CSSPropertyWidth:
-    case CSSPropertyWebkitLogicalWidth:
-        validPrimitive = (id == CSSValueAuto || validWidth(value));
-        break;
-
     case CSSPropertyMaxHeight:
     case CSSPropertyWebkitMaxLogicalHeight:
-        validPrimitive = (id == CSSValueNone || validHeight(value));
+        validPrimitive = (id == CSSValueNone || isValidSize(valueWithCalculation));
         break;
 
+    case CSSPropertyMinWidth:
+    case CSSPropertyWebkitMinLogicalWidth:
     case CSSPropertyMinHeight:
     case CSSPropertyWebkitMinLogicalHeight:
-        validPrimitive = validHeight(value);
+        validPrimitive = id == CSSValueAuto || isValidSize(valueWithCalculation);
         break;
 
+    case CSSPropertyWidth:
+    case CSSPropertyWebkitLogicalWidth:
     case CSSPropertyHeight:
     case CSSPropertyWebkitLogicalHeight:
-        validPrimitive = (id == CSSValueAuto || validHeight(value));
+        validPrimitive = (id == CSSValueAuto || isValidSize(valueWithCalculation));
         break;
 
     case CSSPropertyFontSize:
         return parseFontSize(important);
 
-    case CSSPropertyFontVariant:         // normal | small-caps | inherit
-        return parseFontVariant(important);
-
     case CSSPropertyVerticalAlign:
         // baseline | sub | super | top | text-top | middle | bottom | text-bottom |
         // <percentage> | <length> | inherit
@@ -2258,7 +2357,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         if (id >= CSSValueBaseline && id <= CSSValueWebkitBaselineMiddle)
             validPrimitive = true;
         else
-            validPrimitive = (!id && validUnit(value, FLength | FPercent));
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FLength | FPercent));
         break;
 
     case CSSPropertyBottom:               // <length> | <percentage> | auto | inherit
@@ -2276,21 +2375,22 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         if (id == CSSValueAuto)
             validPrimitive = true;
         else
-            validPrimitive = (!id && validUnit(value, FLength | FPercent));
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FLength | FPercent));
         break;
 
     case CSSPropertyZIndex:              // auto | <integer> | inherit
-        if (id == CSSValueAuto) {
+        if (id == CSSValueAuto)
             validPrimitive = true;
-            break;
-        }
-        /* nobreak */
+        else
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FInteger, CSSQuirksMode));
+        break;
+
     case CSSPropertyOrphans: // <integer> | inherit | auto (We've added support for auto for backwards compatibility)
     case CSSPropertyWidows: // <integer> | inherit | auto (Ditto)
         if (id == CSSValueAuto)
             validPrimitive = true;
         else
-            validPrimitive = (!id && validUnit(value, FInteger, CSSQuirksMode));
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FPositiveInteger, CSSQuirksMode));
         break;
 
     case CSSPropertyLineHeight:
@@ -2312,53 +2412,47 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         break;
     }
 
+    case CSSPropertyWebkitTextDecoration:
+        // [ <text-decoration-line> || <text-decoration-style> || <text-decoration-color> ] | inherit
+        return parseShorthand(CSSPropertyWebkitTextDecoration, webkitTextDecorationShorthand(), important);
+
     case CSSPropertyTextDecoration:
     case CSSPropertyWebkitTextDecorationsInEffect:
-#if ENABLE(CSS3_TEXT)
     case CSSPropertyWebkitTextDecorationLine:
-#endif // CSS3_TEXT
         // none | [ underline || overline || line-through || blink ] | inherit
         return parseTextDecoration(propId, important);
 
-#if ENABLE(CSS3_TEXT)
     case CSSPropertyWebkitTextDecorationStyle:
         // solid | double | dotted | dashed | wavy
         if (id == CSSValueSolid || id == CSSValueDouble || id == CSSValueDotted || id == CSSValueDashed || id == CSSValueWavy)
             validPrimitive = true;
         break;
 
+    case CSSPropertyWebkitTextDecorationSkip:
+        // none | [ objects || spaces || ink || edges || box-decoration ]
+        return parseTextDecorationSkip(important);
+
     case CSSPropertyWebkitTextUnderlinePosition:
         // auto | alphabetic | under
         return parseTextUnderlinePosition(important);
-#endif // CSS3_TEXT
 
-    case CSSPropertyZoom:          // normal | reset | document | <number> | <percentage> | inherit
+    case CSSPropertyZoom:
+        // normal | reset | document | <number> | <percentage> | inherit
         if (id == CSSValueNormal || id == CSSValueReset || id == CSSValueDocument)
             validPrimitive = true;
         else
-            validPrimitive = (!id && validUnit(value, FNumber | FPercent | FNonNeg, CSSStrictMode));
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FNumber | FPercent | FNonNeg, CSSStrictMode));
+        break;
+    
+    case CSSPropertyWebkitTextZoom:
+        // normal | reset
+        if (id == CSSValueNormal || id == CSSValueReset)
+            validPrimitive = true;
         break;
 
     case CSSPropertySrc: // Only used within @font-face and @-webkit-filter, so cannot use inherit | initial or be !important. This is a list of urls or local references.
-#if ENABLE(CSS_SHADERS)
-        if (m_inFilterRule)
-            return parseFilterRuleSrc();
-#endif
         return parseFontFaceSrc();
 
-#if ENABLE(CSS_SHADERS)
-    case CSSPropertyMix:
-        // The mix property is just supported inside of an @filter rule.
-        if (!m_inFilterRule)
-            return false;
-        return parseFilterRuleMix();
-    case CSSPropertyParameters:
-        // The parameters property is just supported inside of an @filter rule.
-        if (!m_inFilterRule)
-            return false;
-        return parseFilterRuleParameters();
-#endif
-
     case CSSPropertyUnicodeRange:
         return parseFontFaceUnicodeRange();
 
@@ -2419,17 +2513,17 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyBorderBottomRightRadius: {
         if (num != 1 && num != 2)
             return false;
-        validPrimitive = validUnit(value, FLength | FPercent | FNonNeg);
+        validPrimitive = validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg);
         if (!validPrimitive)
             return false;
-        RefPtr<CSSPrimitiveValue> parsedValue1 = createPrimitiveNumericValue(value);
+        RefPtr<CSSPrimitiveValue> parsedValue1 = createPrimitiveNumericValue(valueWithCalculation);
         RefPtr<CSSPrimitiveValue> parsedValue2;
         if (num == 2) {
-            value = m_valueList->next();
-            validPrimitive = validUnit(value, FLength | FPercent | FNonNeg);
+            ValueWithCalculation nextValueWithCalculation(*m_valueList->next());
+            validPrimitive = validateUnit(nextValueWithCalculation, FLength | FPercent | FNonNeg);
             if (!validPrimitive)
                 return false;
-            parsedValue2 = createPrimitiveNumericValue(value);
+            parsedValue2 = createPrimitiveNumericValue(nextValueWithCalculation);
         } else
             parsedValue2 = parsedValue1;
 
@@ -2437,7 +2531,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         return true;
     }
     case CSSPropertyTabSize:
-        validPrimitive = validUnit(value, FInteger | FNonNeg);
+        validPrimitive = validateUnit(valueWithCalculation, FInteger | FNonNeg);
         break;
     case CSSPropertyWebkitAspectRatio:
         return parseAspectRatio(important);
@@ -2445,7 +2539,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitBorderRadius:
         return parseBorderRadius(propId, important);
     case CSSPropertyOutlineOffset:
-        validPrimitive = validUnit(value, FLength | FPercent);
+        validPrimitive = validateUnit(valueWithCalculation, FLength);
         break;
     case CSSPropertyTextShadow: // CSS2 property, dropped in CSS2.1, back in CSS3, so treat as CSS3
     case CSSPropertyBoxShadow:
@@ -2453,7 +2547,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         if (id == CSSValueNone)
             validPrimitive = true;
         else {
-            RefPtr<CSSValueList> shadowValueList = parseShadow(m_valueList.get(), propId);
+            RefPtr<CSSValueList> shadowValueList = parseShadow(*m_valueList, propId);
             if (shadowValueList) {
                 addProperty(propId, shadowValueList.release(), important);
                 m_valueList->next();
@@ -2462,6 +2556,30 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             return false;
         }
         break;
+    case CSSPropertyWebkitInitialLetter: {
+        if (id == CSSValueNormal)
+            validPrimitive = true;
+        else {
+            if (num != 1 && num != 2)
+                return false;
+            validPrimitive = validateUnit(valueWithCalculation, FPositiveInteger);
+            if (!validPrimitive)
+                return false;
+            RefPtr<CSSPrimitiveValue> height = createPrimitiveNumericValue(valueWithCalculation);
+            RefPtr<CSSPrimitiveValue> position;
+            if (num == 2) {
+                ValueWithCalculation nextValueWithCalculation(*m_valueList->next());
+                validPrimitive = validateUnit(nextValueWithCalculation, FPositiveInteger);
+                if (!validPrimitive)
+                    return false;
+                position = createPrimitiveNumericValue(nextValueWithCalculation);
+            } else
+                position = height;
+            addProperty(propId, createPrimitiveValuePair(position.release(), height.release()), important);
+            return true;
+        }
+        break;
+    }
     case CSSPropertyWebkitBoxReflect:
         if (id == CSSValueNone)
             validPrimitive = true;
@@ -2469,63 +2587,67 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             return parseReflect(propId, important);
         break;
     case CSSPropertyOpacity:
-        validPrimitive = validUnit(value, FNumber);
+        validPrimitive = validateUnit(valueWithCalculation, FNumber);
         break;
     case CSSPropertyWebkitBoxFlex:
-        validPrimitive = validUnit(value, FNumber);
+        validPrimitive = validateUnit(valueWithCalculation, FNumber);
         break;
     case CSSPropertyWebkitBoxFlexGroup:
-        validPrimitive = validUnit(value, FInteger | FNonNeg, CSSStrictMode);
+        validPrimitive = validateUnit(valueWithCalculation, FInteger | FNonNeg, CSSStrictMode);
         break;
     case CSSPropertyWebkitBoxOrdinalGroup:
-        validPrimitive = validUnit(value, FInteger | FNonNeg, CSSStrictMode) && value->fValue;
+        validPrimitive = validateUnit(valueWithCalculation, FInteger | FNonNeg, CSSStrictMode) && valueWithCalculation.value().fValue;
         break;
-#if ENABLE(CSS_FILTERS)
-    case CSSPropertyWebkitFilter:
+    case CSSPropertyFilter:
+#if ENABLE(FILTERS_LEVEL_2)
+    case CSSPropertyWebkitBackdropFilter:
+#endif
         if (id == CSSValueNone)
             validPrimitive = true;
         else {
-            RefPtr<CSSValue> val = parseFilter();
-            if (val) {
-                addProperty(propId, val, important);
-                return true;
-            }
-            return false;
+            RefPtr<CSSValue> currValue;
+            if (!parseFilter(*m_valueList, currValue))
+                return false;
+            addProperty(propId, currValue, important);
+            return true;
         }
         break;
-#endif
 #if ENABLE(CSS_COMPOSITING)
-    case CSSPropertyWebkitBlendMode:
+    case CSSPropertyMixBlendMode:
+        if (cssCompositingEnabled())
+            validPrimitive = true;
+        break;
+    case CSSPropertyIsolation:
         if (cssCompositingEnabled())
             validPrimitive = true;
         break;
 #endif
-    case CSSPropertyWebkitFlex: {
+    case CSSPropertyFlex: {
         ShorthandScope scope(this, propId);
         if (id == CSSValueNone) {
-            addProperty(CSSPropertyWebkitFlexGrow, cssValuePool().createValue(0, CSSPrimitiveValue::CSS_NUMBER), important);
-            addProperty(CSSPropertyWebkitFlexShrink, cssValuePool().createValue(0, CSSPrimitiveValue::CSS_NUMBER), important);
-            addProperty(CSSPropertyWebkitFlexBasis, cssValuePool().createIdentifierValue(CSSValueAuto), important);
+            addProperty(CSSPropertyFlexGrow, cssValuePool.createValue(0, CSSPrimitiveValue::CSS_NUMBER), important);
+            addProperty(CSSPropertyFlexShrink, cssValuePool.createValue(0, CSSPrimitiveValue::CSS_NUMBER), important);
+            addProperty(CSSPropertyFlexBasis, cssValuePool.createIdentifierValue(CSSValueAuto), important);
             return true;
         }
-        return parseFlex(m_valueList.get(), important);
+        return parseFlex(*m_valueList, important);
     }
-    case CSSPropertyWebkitFlexBasis:
+    case CSSPropertyFlexBasis:
         // FIXME: Support intrinsic dimensions too.
         if (id == CSSValueAuto)
             validPrimitive = true;
         else
-            validPrimitive = (!id && validUnit(value, FLength | FPercent | FNonNeg));
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg));
         break;
-    case CSSPropertyWebkitFlexGrow:
-    case CSSPropertyWebkitFlexShrink:
-        validPrimitive = validUnit(value, FNumber | FNonNeg);
+    case CSSPropertyFlexGrow:
+    case CSSPropertyFlexShrink:
+        validPrimitive = validateUnit(valueWithCalculation, FNumber | FNonNeg);
         break;
-    case CSSPropertyWebkitOrder:
-        if (validUnit(value, FInteger, CSSStrictMode)) {
+    case CSSPropertyOrder:
+        if (validateUnit(valueWithCalculation, FInteger, CSSStrictMode)) {
             // We restrict the smallest value to int min + 2 because we use int min and int min + 1 as special values in a hash set.
-            parsedValue = cssValuePool().createValue(max(static_cast<double>(std::numeric_limits<int>::min() + 2), value->fValue),
-                                                             static_cast<CSSPrimitiveValue::UnitTypes>(value->unit));
+            double result = std::max<double>(std::numeric_limits<int>::min() + 2, parsedDouble(valueWithCalculation));
+            parsedValue = cssValuePool.createValue(result, CSSPrimitiveValue::CSS_NUMBER);
             m_valueList->next();
         }
         break;
@@ -2535,19 +2657,19 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         if (id == CSSValueSmall || id == CSSValueLarge || id == CSSValueMedium)
             validPrimitive = true;
         else
-            validPrimitive = validUnit(value, FLength | FPercent);
+            validPrimitive = validateUnit(valueWithCalculation, FLength | FPercent);
         break;
     case CSSPropertyWebkitMarqueeRepetition:
         if (id == CSSValueInfinite)
             validPrimitive = true;
         else
-            validPrimitive = validUnit(value, FInteger | FNonNeg);
+            validPrimitive = validateUnit(valueWithCalculation, FInteger | FNonNeg);
         break;
     case CSSPropertyWebkitMarqueeSpeed:
         if (id == CSSValueNormal || id == CSSValueSlow || id == CSSValueFast)
             validPrimitive = true;
         else
-            validPrimitive = validUnit(value, FTime | FInteger | FNonNeg);
+            validPrimitive = validateUnit(valueWithCalculation, FTime | FInteger | FNonNeg);
         break;
 #if ENABLE(CSS_REGIONS)
     case CSSPropertyWebkitFlowInto:
@@ -2559,7 +2681,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             return false;
         return parseRegionThread(propId, important);
 #endif
-    case CSSPropertyWebkitTransform:
+    case CSSPropertyTransform:
         if (id == CSSValueNone)
             validPrimitive = true;
         else {
@@ -2571,12 +2693,12 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             return false;
         }
         break;
-    case CSSPropertyWebkitTransformOrigin:
-    case CSSPropertyWebkitTransformOriginX:
-    case CSSPropertyWebkitTransformOriginY:
-    case CSSPropertyWebkitTransformOriginZ: {
-        RefPtr<CSSValue> val1;
-        RefPtr<CSSValue> val2;
+    case CSSPropertyTransformOrigin:
+    case CSSPropertyTransformOriginX:
+    case CSSPropertyTransformOriginY:
+    case CSSPropertyTransformOriginZ: {
+        RefPtr<CSSPrimitiveValue> val1;
+        RefPtr<CSSPrimitiveValue> val2;
         RefPtr<CSSValue> val3;
         CSSPropertyID propId1, propId2, propId3;
         if (parseTransformOrigin(propId, propId1, propId2, propId3, val1, val2, val3)) {
@@ -2589,13 +2711,13 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         }
         return false;
     }
-    case CSSPropertyWebkitPerspective:
+    case CSSPropertyPerspective:
         if (id == CSSValueNone)
             validPrimitive = true;
         else {
             // Accepting valueless numbers is a quirk of the -webkit prefixed version of the property.
-            if (validUnit(value, FNumber | FLength | FNonNeg)) {
-                RefPtr<CSSValue> val = createPrimitiveNumericValue(value);
+            if (validateUnit(valueWithCalculation, FNumber | FLength | FNonNeg)) {
+                RefPtr<CSSValue> val = createPrimitiveNumericValue(valueWithCalculation);
                 if (val) {
                     addProperty(propId, val.release(), important);
                     return true;
@@ -2604,11 +2726,11 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             }
         }
         break;
-    case CSSPropertyWebkitPerspectiveOrigin:
-    case CSSPropertyWebkitPerspectiveOriginX:
-    case CSSPropertyWebkitPerspectiveOriginY: {
-        RefPtr<CSSValue> val1;
-        RefPtr<CSSValue> val2;
+    case CSSPropertyPerspectiveOrigin:
+    case CSSPropertyPerspectiveOriginX:
+    case CSSPropertyPerspectiveOriginY: {
+        RefPtr<CSSPrimitiveValue> val1;
+        RefPtr<CSSPrimitiveValue> val2;
         CSSPropertyID propId1, propId2;
         if (parsePerspectiveOrigin(propId, propId1, propId2, val1, val2)) {
             addProperty(propId1, val1.release(), important);
@@ -2618,6 +2740,14 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         }
         return false;
     }
+    case CSSPropertyAnimationDelay:
+    case CSSPropertyAnimationDirection:
+    case CSSPropertyAnimationDuration:
+    case CSSPropertyAnimationFillMode:
+    case CSSPropertyAnimationName:
+    case CSSPropertyAnimationPlayState:
+    case CSSPropertyAnimationIterationCount:
+    case CSSPropertyAnimationTimingFunction:
     case CSSPropertyWebkitAnimationDelay:
     case CSSPropertyWebkitAnimationDirection:
     case CSSPropertyWebkitAnimationDuration:
@@ -2626,6 +2756,9 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitAnimationPlayState:
     case CSSPropertyWebkitAnimationIterationCount:
     case CSSPropertyWebkitAnimationTimingFunction:
+#if ENABLE(CSS_ANIMATIONS_LEVEL_2)
+    case CSSPropertyWebkitAnimationTrigger:
+#endif
     case CSSPropertyTransitionDelay:
     case CSSPropertyTransitionDuration:
     case CSSPropertyTransitionTimingFunction:
@@ -2642,38 +2775,63 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         }
         return false;
     }
-
+    case CSSPropertyJustifyContent:
+        parsedValue = parseContentDistributionOverflowPosition();
+        break;
+    case CSSPropertyJustifySelf:
+        return parseItemPositionOverflowPosition(propId, important);
+    case CSSPropertyJustifyItems:
+        if (parseLegacyPosition(propId, important))
+            return true;
+        m_valueList->setCurrentIndex(0);
+        return parseItemPositionOverflowPosition(propId, important);
+#if ENABLE(CSS_GRID_LAYOUT)
     case CSSPropertyWebkitGridAutoColumns:
     case CSSPropertyWebkitGridAutoRows:
-        if (!cssGridLayoutEnabled())
-            return false;
-        parsedValue = parseGridTrackSize();
+        parsedValue = parseGridTrackSize(*m_valueList);
         break;
 
-    case CSSPropertyWebkitGridDefinitionColumns:
-    case CSSPropertyWebkitGridDefinitionRows:
-        if (!cssGridLayoutEnabled())
-            return false;
-        return parseGridTrackList(propId, important);
+    case CSSPropertyWebkitGridTemplateColumns:
+    case CSSPropertyWebkitGridTemplateRows:
+        parsedValue = parseGridTrackList();
+        break;
 
-    case CSSPropertyWebkitGridStart:
-    case CSSPropertyWebkitGridEnd:
-    case CSSPropertyWebkitGridBefore:
-    case CSSPropertyWebkitGridAfter:
-        if (!cssGridLayoutEnabled())
-            return false;
+    case CSSPropertyWebkitGridColumnStart:
+    case CSSPropertyWebkitGridColumnEnd:
+    case CSSPropertyWebkitGridRowStart:
+    case CSSPropertyWebkitGridRowEnd:
+        parsedValue = parseGridPosition();
+        break;
 
-        validPrimitive = id == CSSValueAuto || (validUnit(value, FInteger) && value->fValue);
+    case CSSPropertyWebkitGridColumnGap:
+    case CSSPropertyWebkitGridRowGap:
+        validPrimitive = validateUnit(valueWithCalculation, FLength | FNonNeg);
         break;
 
+    case CSSPropertyWebkitGridGap:
+        return parseGridGapShorthand(important);
+
     case CSSPropertyWebkitGridColumn:
     case CSSPropertyWebkitGridRow: {
-        if (!cssGridLayoutEnabled())
-            return false;
-
         return parseGridItemPositionShorthand(propId, important);
     }
 
+    case CSSPropertyWebkitGridTemplate:
+        return parseGridTemplateShorthand(important);
+
+    case CSSPropertyWebkitGrid:
+        return parseGridShorthand(important);
+
+    case CSSPropertyWebkitGridArea:
+        return parseGridAreaShorthand(important);
+
+    case CSSPropertyWebkitGridTemplateAreas:
+        parsedValue = parseGridTemplateAreas();
+        break;
+    case CSSPropertyWebkitGridAutoFlow:
+        parsedValue = parseGridAutoFlow(*m_valueList);
+        break;
+#endif /* ENABLE(CSS_GRID_LAYOUT) */
     case CSSPropertyWebkitMarginCollapse: {
         if (num == 1) {
             ShorthandScope scope(this, CSSPropertyWebkitMarginCollapse);
@@ -2698,109 +2856,115 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
             id == CSSValueMedium || id == CSSValueThick)
             validPrimitive = true;
         else
-            validPrimitive = !id && validUnit(value, FNumber | FLength | FPercent);
+            validPrimitive = !id && validateUnit(valueWithCalculation, FNumber | FLength | FPercent);
         break;
-    case CSSPropertyWebkitColumnCount:
-        if (id == CSSValueAuto)
-            validPrimitive = true;
-        else
-            validPrimitive = !id && validUnit(value, FPositiveInteger, CSSQuirksMode);
+    case CSSPropertyColumnCount:
+        parsedValue = parseColumnCount();
         break;
-    case CSSPropertyWebkitColumnGap:         // normal | <length>
+    case CSSPropertyColumnGap: // normal | <length>
         if (id == CSSValueNormal)
             validPrimitive = true;
         else
-            validPrimitive = validUnit(value, FLength | FNonNeg);
+            validPrimitive = validateUnit(valueWithCalculation, FLength | FNonNeg);
         break;
     case CSSPropertyWebkitColumnAxis:
         if (id == CSSValueHorizontal || id == CSSValueVertical || id == CSSValueAuto)
             validPrimitive = true;
         break;
-    case CSSPropertyWebkitColumnProgression:
+    case CSSPropertyColumnProgression:
         if (id == CSSValueNormal || id == CSSValueReverse)
             validPrimitive = true;
         break;
-    case CSSPropertyWebkitColumnSpan: // none | all | 1 (will be dropped in the unprefixed property)
+    case CSSPropertyColumnSpan: // none | all | 1 (will be dropped in the unprefixed property)
         if (id == CSSValueAll || id == CSSValueNone)
             validPrimitive = true;
-        else
-            validPrimitive = validUnit(value, FNumber | FNonNeg) && value->fValue == 1;
+        else if (validateUnit(valueWithCalculation, FNumber | FNonNeg) && parsedDouble(valueWithCalculation) == 1) {
+            addProperty(CSSPropertyColumnSpan, cssValuePool.createValue(1, CSSPrimitiveValue::CSS_NUMBER), important);
+            return true;
+        }
         break;
-    case CSSPropertyWebkitColumnWidth:         // auto | <length>
+    case CSSPropertyColumnWidth: // auto | <length>
+        parsedValue = parseColumnWidth();
+        break;
+    // End of CSS3 properties
+
+    case CSSPropertyWillChange: // auto | [scroll-position | contents | <custom-ident>]#
         if (id == CSSValueAuto)
             validPrimitive = true;
-        else // Always parse this property in strict mode, since it would be ambiguous otherwise when used in the 'columns' shorthand property.
-            validPrimitive = validUnit(value, FLength | FNonNeg, CSSStrictMode) && value->fValue;
+        else
+            return parseWillChange(important);
         break;
-    // End of CSS3 properties
 
     // Apple specific properties.  These will never be standardized and are purely to
     // support custom WebKit-based Apple applications.
     case CSSPropertyWebkitLineClamp:
         // When specifying number of lines, don't allow 0 as a valid value
         // When specifying either type of unit, require non-negative integers
-        validPrimitive = (!id && (value->unit == CSSPrimitiveValue::CSS_PERCENTAGE || value->fValue) && validUnit(value, FInteger | FPercent | FNonNeg, CSSQuirksMode));
+        validPrimitive = (!id && (valueWithCalculation.value().unit == CSSPrimitiveValue::CSS_PERCENTAGE || valueWithCalculation.value().fValue) && validateUnit(valueWithCalculation, FInteger | FPercent | FNonNeg, CSSQuirksMode));
         break;
-
-    case CSSPropertyWebkitFontSizeDelta:           // <length>
-        validPrimitive = validUnit(value, FLength);
+#if ENABLE(IOS_TEXT_AUTOSIZING)
+    case CSSPropertyWebkitTextSizeAdjust:
+        if (id == CSSValueAuto || id == CSSValueNone)
+            validPrimitive = true;
+        else {
+            // FIXME: Handle multilength case where we allow relative units.
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FPercent | FNonNeg, CSSStrictMode));
+        }
         break;
+#endif
 
-    case CSSPropertyWebkitHighlight:
-        if (id == CSSValueNone || value->unit == CSSPrimitiveValue::CSS_STRING)
-            validPrimitive = true;
+    case CSSPropertyWebkitFontSizeDelta:           // <length>
+        validPrimitive = validateUnit(valueWithCalculation, FLength);
         break;
 
     case CSSPropertyWebkitHyphenateCharacter:
-        if (id == CSSValueAuto || value->unit == CSSPrimitiveValue::CSS_STRING)
+        if (id == CSSValueAuto || valueWithCalculation.value().unit == CSSPrimitiveValue::CSS_STRING)
             validPrimitive = true;
         break;
 
     case CSSPropertyWebkitHyphenateLimitBefore:
     case CSSPropertyWebkitHyphenateLimitAfter:
-        if (id == CSSValueAuto || validUnit(value, FInteger | FNonNeg, CSSStrictMode))
+        if (id == CSSValueAuto || validateUnit(valueWithCalculation, FInteger | FNonNeg, CSSStrictMode))
             validPrimitive = true;
         break;
 
     case CSSPropertyWebkitHyphenateLimitLines:
-        if (id == CSSValueNoLimit || validUnit(value, FInteger | FNonNeg, CSSStrictMode))
+        if (id == CSSValueNoLimit || validateUnit(valueWithCalculation, FInteger | FNonNeg, CSSStrictMode))
             validPrimitive = true;
         break;
 
     case CSSPropertyWebkitLineGrid:
         if (id == CSSValueNone)
             validPrimitive = true;
-        else if (value->unit == CSSPrimitiveValue::CSS_IDENT) {
-            String lineGridValue = String(value->string);
+        else if (valueWithCalculation.value().unit == CSSPrimitiveValue::CSS_IDENT) {
+            String lineGridValue = String(valueWithCalculation.value().string);
             if (!lineGridValue.isEmpty()) {
-                addProperty(propId, cssValuePool().createValue(lineGridValue, CSSPrimitiveValue::CSS_STRING), important);
+                addProperty(propId, cssValuePool.createValue(lineGridValue, CSSPrimitiveValue::CSS_STRING), important);
                 return true;
             }
         }
         break;
     case CSSPropertyWebkitLocale:
-        if (id == CSSValueAuto || value->unit == CSSPrimitiveValue::CSS_STRING)
+        if (id == CSSValueAuto || valueWithCalculation.value().unit == CSSPrimitiveValue::CSS_STRING)
             validPrimitive = true;
         break;
 
 #if ENABLE(DASHBOARD_SUPPORT)
     case CSSPropertyWebkitDashboardRegion: // <dashboard-region> | <dashboard-region>
-        if (value->unit == CSSParserValue::Function || id == CSSValueNone)
+        if (valueWithCalculation.value().unit == CSSParserValue::Function || id == CSSValueNone)
             return parseDashboardRegions(propId, important);
         break;
 #endif
-    // End Apple-specific properties
 
-#if ENABLE(DRAGGABLE_REGION)
-    case CSSPropertyWebkitAppRegion:
-        if (id >= CSSValueDrag && id <= CSSValueNoDrag)
+#if PLATFORM(IOS)
+    case CSSPropertyWebkitTouchCallout:
+        if (id == CSSValueDefault || id == CSSValueNone)
             validPrimitive = true;
         break;
 #endif
-
 #if ENABLE(TOUCH_EVENTS)
     case CSSPropertyWebkitTapHighlightColor:
-        if ((id >= CSSValueAqua && id <= CSSValueWindowtext) || id == CSSValueMenu
+        if (isValidSystemColorValue(id) || id == CSSValueMenu
             || (id >= CSSValueWebkitFocusRingColor && id < CSSValueWebkitText && inQuirksMode())) {
             validPrimitive = true;
         } else {
@@ -2810,6 +2974,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         }
         break;
 #endif
+    // End Apple-specific properties
 
         /* shorthand properties */
     case CSSPropertyBackground: {
@@ -2821,7 +2986,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         return parseFillShorthand(propId, properties, WTF_ARRAY_LENGTH(properties), important);
     }
     case CSSPropertyWebkitMask: {
-        const CSSPropertyID properties[] = { CSSPropertyWebkitMaskImage, CSSPropertyWebkitMaskRepeat,
+        const CSSPropertyID properties[] = { CSSPropertyWebkitMaskImage, CSSPropertyWebkitMaskSourceType, CSSPropertyWebkitMaskRepeat,
             CSSPropertyWebkitMaskPosition, CSSPropertyWebkitMaskOrigin, CSSPropertyWebkitMaskClip, CSSPropertyWebkitMaskSize };
         return parseFillShorthand(propId, properties, WTF_ARRAY_LENGTH(properties), important);
     }
@@ -2831,7 +2996,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         if (parseShorthand(propId, borderAbridgedShorthand(), important)) {
             // The CSS3 Borders and Backgrounds specification says that border also resets border-image. It's as
             // though a value of none was specified for the image.
-            addExpandedPropertyForValue(CSSPropertyBorderImage, cssValuePool().createImplicitInitialValue(), important);
+            addExpandedPropertyForValue(CSSPropertyBorderImage, cssValuePool.createImplicitInitialValue(), important);
             return true;
         }
         return false;
@@ -2874,26 +3039,27 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyPadding:
         // <padding-width>{1,4} | inherit
         return parse4Values(propId, paddingShorthand().properties(), important);
-    case CSSPropertyWebkitFlexFlow:
-        return parseShorthand(propId, webkitFlexFlowShorthand(), important);
+    case CSSPropertyFlexFlow:
+        return parseShorthand(propId, flexFlowShorthand(), important);
     case CSSPropertyFont:
         // [ [ 'font-style' || 'font-variant' || 'font-weight' ]? 'font-size' [ / 'line-height' ]?
         // 'font-family' ] | caption | icon | menu | message-box | small-caption | status-bar | inherit
-        if (id >= CSSValueCaption && id <= CSSValueStatusBar)
-            validPrimitive = true;
-        else
-            return parseFont(important);
-        break;
+        if (num == 1 && id >= CSSValueCaption && id <= CSSValueStatusBar) {
+            parseSystemFont(important);
+            return true;
+        }
+        return parseFont(important);
     case CSSPropertyListStyle:
         return parseShorthand(propId, listStyleShorthand(), important);
-    case CSSPropertyWebkitColumns:
-        return parseShorthand(propId, webkitColumnsShorthand(), important);
-    case CSSPropertyWebkitColumnRule:
-        return parseShorthand(propId, webkitColumnRuleShorthand(), important);
+    case CSSPropertyColumns:
+        return parseColumnsShorthand(important);
+    case CSSPropertyColumnRule:
+        return parseShorthand(propId, columnRuleShorthand(), important);
     case CSSPropertyWebkitTextStroke:
         return parseShorthand(propId, webkitTextStrokeShorthand(), important);
+    case CSSPropertyAnimation:
     case CSSPropertyWebkitAnimation:
-        return parseAnimationShorthand(important);
+        return parseAnimationShorthand(propId, important);
     case CSSPropertyTransition:
     case CSSPropertyWebkitTransition:
         return parseTransitionShorthand(propId, important);
@@ -2901,10 +3067,6 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         return false;
     case CSSPropertyPage:
         return parsePage(propId, important);
-#if ENABLE(CSS_SHADERS)
-    case CSSPropertyGeometry:
-        return m_inFilterRule ? parseGeometry(propId, value, important) : false;
-#endif
     case CSSPropertyFontStretch:
     case CSSPropertyTextLineThrough:
     case CSSPropertyTextOverline:
@@ -2917,68 +3079,81 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitTextEmphasisStyle:
         return parseTextEmphasisStyle(important);
 
+    case CSSPropertyWebkitTextEmphasisPosition:
+        return parseTextEmphasisPosition(important);
+
     case CSSPropertyWebkitTextOrientation:
-        // FIXME: For now just support sideways, sideways-right, upright and vertical-right.
-        if (id == CSSValueSideways || id == CSSValueSidewaysRight || id == CSSValueVerticalRight || id == CSSValueUpright)
+        if (id == CSSValueSideways || id == CSSValueSidewaysRight || id == CSSValueVerticalRight || id == CSSValueMixed || id == CSSValueUpright)
             validPrimitive = true;
         break;
 
+    case CSSPropertyHangingPunctuation:
+        return parseHangingPunctuation(important);
     case CSSPropertyWebkitLineBoxContain:
         if (id == CSSValueNone)
             validPrimitive = true;
         else
             return parseLineBoxContain(important);
         break;
-    case CSSPropertyWebkitFontFeatureSettings:
+    case CSSPropertyFontFeatureSettings:
         if (id == CSSValueNormal)
             validPrimitive = true;
         else
             return parseFontFeatureSettings(important);
         break;
-
-    case CSSPropertyWebkitFontVariantLigatures:
+    case CSSPropertyFontVariantLigatures:
+        if (id == CSSValueNormal || id == CSSValueNone)
+            validPrimitive = true;
+        else
+            return parseFontVariantLigatures(important, true, false);
+        break;
+    case CSSPropertyFontVariantNumeric:
         if (id == CSSValueNormal)
             validPrimitive = true;
         else
-            return parseFontVariantLigatures(important);
+            return parseFontVariantNumeric(important, true, false);
         break;
-    case CSSPropertyWebkitClipPath:
-        if (id == CSSValueNone)
+    case CSSPropertyFontVariantEastAsian:
+        if (id == CSSValueNormal)
             validPrimitive = true;
-        else if (value->unit == CSSParserValue::Function)
-            return parseBasicShape(propId, important);
-#if ENABLE(SVG)
-        else if (value->unit == CSSPrimitiveValue::CSS_URI) {
-            parsedValue = CSSPrimitiveValue::create(value->string, CSSPrimitiveValue::CSS_URI);
-            addProperty(propId, parsedValue.release(), important);
+        else
+            return parseFontVariantEastAsian(important, true, false);
+        break;
+    case CSSPropertyFontVariant:
+        if (id == CSSValueNormal) {
+            ShorthandScope scope(this, CSSPropertyFontVariant);
+            addProperty(CSSPropertyFontVariantLigatures, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
+            addProperty(CSSPropertyFontVariantPosition, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
+            addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
+            addProperty(CSSPropertyFontVariantNumeric, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
+            addProperty(CSSPropertyFontVariantAlternates, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
+            addProperty(CSSPropertyFontVariantEastAsian, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
             return true;
         }
-#endif
+        if (id == CSSValueNone) {
+            ShorthandScope scope(this, CSSPropertyFontVariant);
+            addProperty(CSSPropertyFontVariantLigatures, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important, true);
+            return true;
+        }
+        return parseFontVariant(important);
+
+    case CSSPropertyWebkitClipPath:
+        parsedValue = parseClipPath();
         break;
 #if ENABLE(CSS_SHAPES)
-    case CSSPropertyWebkitShapeInside:
     case CSSPropertyWebkitShapeOutside:
-        if (!RuntimeEnabledFeatures::cssShapesEnabled())
-            return false;
-        if (id == CSSValueAuto)
-            validPrimitive = true;
-        else if (propId == CSSPropertyWebkitShapeInside && id == CSSValueOutsideShape)
-            validPrimitive = true;
-        else if (value->unit == CSSParserValue::Function)
-            return parseBasicShape(propId, important);
-        else if (value->unit == CSSPrimitiveValue::CSS_URI) {
-            parsedValue = CSSImageValue::create(completeURL(value->string));
-            m_valueList->next();
-        }
+        parsedValue = parseShapeProperty(propId);
         break;
     case CSSPropertyWebkitShapeMargin:
-    case CSSPropertyWebkitShapePadding:
-        validPrimitive = (RuntimeEnabledFeatures::cssShapesEnabled() && !id && validUnit(value, FLength | FNonNeg));
+        validPrimitive = (RuntimeEnabledFeatures::sharedFeatures().cssShapesEnabled() && !id && validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg));
+        break;
+    case CSSPropertyWebkitShapeImageThreshold:
+        validPrimitive = (RuntimeEnabledFeatures::sharedFeatures().cssShapesEnabled() && !id && validateUnit(valueWithCalculation, FNumber));
         break;
 #endif
 #if ENABLE(CSS_IMAGE_ORIENTATION)
     case CSSPropertyImageOrientation:
-        validPrimitive = !id && validUnit(value, FAngle);
+        validPrimitive = !id && validateUnit(valueWithCalculation, FAngle);
         break;
 #endif
 #if ENABLE(CSS_IMAGE_RESOLUTION)
@@ -2986,12 +3161,23 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         parsedValue = parseImageResolution();
         break;
 #endif
+    case CSSPropertyAlignContent:
+        parsedValue = parseContentDistributionOverflowPosition();
+        break;
+    case CSSPropertyAlignSelf:
+        return parseItemPositionOverflowPosition(propId, important);
+
+    case CSSPropertyAlignItems:
+        return parseItemPositionOverflowPosition(propId, important);
     case CSSPropertyBorderBottomStyle:
     case CSSPropertyBorderCollapse:
     case CSSPropertyBorderLeftStyle:
     case CSSPropertyBorderRightStyle:
     case CSSPropertyBorderTopStyle:
     case CSSPropertyBoxSizing:
+    case CSSPropertyBreakAfter:
+    case CSSPropertyBreakBefore:
+    case CSSPropertyBreakInside:
     case CSSPropertyCaptionSide:
     case CSSPropertyClear:
     case CSSPropertyDirection:
@@ -3002,6 +3188,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyImageRendering:
     case CSSPropertyListStylePosition:
     case CSSPropertyListStyleType:
+    case CSSPropertyObjectFit:
     case CSSPropertyOutlineStyle:
     case CSSPropertyOverflowWrap:
     case CSSPropertyOverflowX:
@@ -3023,9 +3210,6 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyTextTransform:
     case CSSPropertyTextUnderlineMode:
     case CSSPropertyTextUnderlineStyle:
-#if ENABLE(CSS_VARIABLES)
-    case CSSPropertyVariable:
-#endif
     case CSSPropertyVisibility:
     case CSSPropertyWebkitAppearance:
     case CSSPropertyWebkitBackfaceVisibility:
@@ -3042,21 +3226,16 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitBoxLines:
     case CSSPropertyWebkitBoxOrient:
     case CSSPropertyWebkitBoxPack:
-    case CSSPropertyWebkitColorCorrection:
     case CSSPropertyWebkitColumnBreakAfter:
     case CSSPropertyWebkitColumnBreakBefore:
     case CSSPropertyWebkitColumnBreakInside:
-    case CSSPropertyWebkitColumnRuleStyle:
-    case CSSPropertyWebkitAlignContent:
-    case CSSPropertyWebkitAlignItems:
-    case CSSPropertyWebkitAlignSelf:
-    case CSSPropertyWebkitFlexDirection:
-    case CSSPropertyWebkitFlexWrap:
-    case CSSPropertyWebkitJustifyContent:
+    case CSSPropertyColumnFill:
+    case CSSPropertyColumnRuleStyle:
+    case CSSPropertyFlexDirection:
+    case CSSPropertyFlexWrap:
     case CSSPropertyWebkitFontKerning:
     case CSSPropertyWebkitFontSmoothing:
     case CSSPropertyWebkitHyphens:
-    case CSSPropertyWebkitGridAutoFlow:
     case CSSPropertyWebkitLineAlign:
     case CSSPropertyWebkitLineBreak:
     case CSSPropertyWebkitLineSnap:
@@ -3083,23 +3262,28 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitTextAlignLast:
 #endif // CSS3_TEXT
     case CSSPropertyWebkitTextCombine:
-    case CSSPropertyWebkitTextEmphasisPosition:
 #if ENABLE(CSS3_TEXT)
     case CSSPropertyWebkitTextJustify:
 #endif // CSS3_TEXT
     case CSSPropertyWebkitTextSecurity:
+    case CSSPropertyTransformStyle:
     case CSSPropertyWebkitTransformStyle:
     case CSSPropertyWebkitUserDrag:
     case CSSPropertyWebkitUserModify:
     case CSSPropertyWebkitUserSelect:
-#if ENABLE(CSS_EXCLUSIONS)
-    case CSSPropertyWebkitWrapFlow:
-    case CSSPropertyWebkitWrapThrough:
-#endif
     case CSSPropertyWebkitWritingMode:
     case CSSPropertyWhiteSpace:
     case CSSPropertyWordBreak:
     case CSSPropertyWordWrap:
+#if ENABLE(TOUCH_EVENTS)
+    case CSSPropertyTouchAction:
+#endif
+#if ENABLE(CSS_SCROLL_SNAP)
+    case CSSPropertyWebkitScrollSnapType:
+#endif
+#if ENABLE(CSS_TRAILING_WORD)
+    case CSSPropertyAppleTrailingWord:
+#endif
         // These properties should be handled before in isValidKeywordPropertyAndValue().
         ASSERT_NOT_REACHED();
         return false;
@@ -3114,17 +3298,29 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
         validPrimitive = false;
         break;
 #endif
-#if ENABLE(SVG)
+#if ENABLE(CSS_SCROLL_SNAP)
+    case CSSPropertyWebkitScrollSnapPointsX:
+    case CSSPropertyWebkitScrollSnapPointsY:
+        if (id == CSSValueElements) {
+            validPrimitive = true;
+            break;
+        }
+        return parseNonElementSnapPoints(propId, important);
+    case CSSPropertyWebkitScrollSnapDestination: // <length>{2}
+        return parseScrollSnapDestination(propId, important);
+    case CSSPropertyWebkitScrollSnapCoordinate:
+        return parseScrollSnapCoordinate(propId, important);
+#endif
+
     default:
         return parseSVGValue(propId, important);
-#endif
     }
 
     if (validPrimitive) {
-        parsedValue = parseValidPrimitive(id, value);
+        parsedValue = parseValidPrimitive(id, valueWithCalculation);
         m_valueList->next();
     }
-    ASSERT(!m_parsedCalculation);
+
     if (parsedValue) {
         if (!m_valueList->current() || inShorthand()) {
             addProperty(propId, parsedValue.release(), important);
@@ -3134,28 +3330,186 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     return false;
 }
 
-void CSSParser::addFillValue(RefPtr<CSSValue>& lval, PassRefPtr<CSSValue> rval)
+void CSSParser::addFillValue(RefPtr<CSSValue>& lval, Ref<CSSValue>&& rval)
 {
-    if (lval) {
-        if (lval->isBaseValueList())
-            static_cast<CSSValueList*>(lval.get())->append(rval);
-        else {
-            PassRefPtr<CSSValue> oldlVal(lval.release());
-            PassRefPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
-            list->append(oldlVal);
-            list->append(rval);
-            lval = list;
-        }
+    if (!lval) {
+        lval = WTFMove(rval);
+        return;
     }
+
+    if (lval->isBaseValueList()) {
+        downcast<CSSValueList>(*lval).append(WTFMove(rval));
+        return;
+    }
+
+    auto list = CSSValueList::createCommaSeparated();
+    list.get().append(lval.releaseNonNull());
+    list.get().append(WTFMove(rval));
+    lval = WTFMove(list);
+}
+
+static bool isContentDistributionKeyword(CSSValueID id)
+{
+    return id == CSSValueSpaceBetween || id == CSSValueSpaceAround
+        || id == CSSValueSpaceEvenly || id == CSSValueStretch;
+}
+
+static bool isContentPositionKeyword(CSSValueID id)
+{
+    return id == CSSValueStart || id == CSSValueEnd || id == CSSValueCenter
+        || id == CSSValueFlexStart || id == CSSValueFlexEnd
+        || id == CSSValueLeft || id == CSSValueRight;
+}
+
+static inline bool isBaselinePositionKeyword(CSSValueID id)
+{
+    return id == CSSValueBaseline || id == CSSValueLastBaseline;
+}
+
+static bool isAlignmentOverflowKeyword(CSSValueID id)
+{
+    return id == CSSValueUnsafe || id == CSSValueSafe;
+}
+
+static bool isItemPositionKeyword(CSSValueID id)
+{
+    return id == CSSValueStart || id == CSSValueEnd || id == CSSValueCenter
+        || id == CSSValueSelfStart || id == CSSValueSelfEnd || id == CSSValueFlexStart
+        || id == CSSValueFlexEnd || id == CSSValueLeft || id == CSSValueRight;
+}
+
+bool CSSParser::parseLegacyPosition(CSSPropertyID propId, bool important)
+{
+    // [ legacy && [ left | right | center ]
+
+    CSSParserValue* value = m_valueList->current();
+    if (!value)
+        return false;
+
+    if (value->id == CSSValueLegacy) {
+        value = m_valueList->next();
+        if (!value)
+            return false;
+        if (value->id != CSSValueCenter && value->id != CSSValueLeft && value->id != CSSValueRight)
+            return false;
+    } else if (value->id == CSSValueCenter || value->id == CSSValueLeft || value->id == CSSValueRight) {
+        if (!m_valueList->next() || m_valueList->current()->id != CSSValueLegacy)
+            return false;
+    } else
+        return false;
+
+    auto& cssValuePool = CSSValuePool::singleton();
+    addProperty(propId, createPrimitiveValuePair(cssValuePool.createIdentifierValue(CSSValueLegacy), cssValuePool.createIdentifierValue(value->id)), important);
+    return !m_valueList->next();
+}
+
+RefPtr<CSSValue> CSSParser::parseContentDistributionOverflowPosition()
+{
+    // auto | <baseline-position> | <content-distribution> || [ <overflow-position>? && <content-position> ]
+    // <baseline-position> = baseline | last-baseline;
+    // <content-distribution> = space-between | space-around | space-evenly | stretch;
+    // <content-position> = center | start | end | flex-start | flex-end | left | right;
+    // <overflow-position> = true | safe
+
+    CSSParserValue* value = m_valueList->current();
+    if (!value)
+        return nullptr;
+
+    // auto | <baseline-position>
+    if (value->id == CSSValueAuto || isBaselinePositionKeyword(value->id)) {
+        m_valueList->next();
+        return CSSContentDistributionValue::create(CSSValueInvalid, value->id, CSSValueInvalid);
+    }
+
+    CSSValueID distribution = CSSValueInvalid;
+    CSSValueID position = CSSValueInvalid;
+    CSSValueID overflow = CSSValueInvalid;
+    while (value) {
+        if (isContentDistributionKeyword(value->id)) {
+            if (distribution != CSSValueInvalid)
+                return nullptr;
+            distribution = value->id;
+        } else if (isContentPositionKeyword(value->id)) {
+            if (position != CSSValueInvalid)
+                return nullptr;
+            position = value->id;
+        } else if (isAlignmentOverflowKeyword(value->id)) {
+            if (overflow != CSSValueInvalid)
+                return nullptr;
+            overflow = value->id;
+        } else
+            return nullptr;
+        value = m_valueList->next();
+    }
+
+    // The grammar states that we should have at least <content-distribution> or
+    // <content-position> ( <content-distribution> || <content-position> ).
+    if (position == CSSValueInvalid && distribution == CSSValueInvalid)
+        return nullptr;
+
+    // The grammar states that <overflow-position> must be associated to <content-position>.
+    if (overflow != CSSValueInvalid && position == CSSValueInvalid)
+        return nullptr;
+
+    return CSSContentDistributionValue::create(distribution, position, overflow);
+}
+
+bool CSSParser::parseItemPositionOverflowPosition(CSSPropertyID propId, bool important)
+{
+    // auto | stretch | <baseline-position> | [<item-position> && <overflow-position>? ]
+    // <baseline-position> = baseline | last-baseline;
+    // <item-position> = center | start | end | self-start | self-end | flex-start | flex-end | left | right;
+    // <overflow-position> = true | safe
+
+    CSSParserValue* value = m_valueList->current();
+    if (!value)
+        return false;
+
+    if (value->id == CSSValueAuto || value->id == CSSValueStretch || isBaselinePositionKeyword(value->id)) {
+        if (m_valueList->next())
+            return false;
+
+        addProperty(propId, CSSValuePool::singleton().createIdentifierValue(value->id), important);
+        return true;
+    }
+
+    RefPtr<CSSPrimitiveValue> position;
+    RefPtr<CSSPrimitiveValue> overflowAlignmentKeyword;
+    if (isItemPositionKeyword(value->id)) {
+        position = CSSValuePool::singleton().createIdentifierValue(value->id);
+        value = m_valueList->next();
+        if (value) {
+            if (value->id != CSSValueUnsafe && value->id != CSSValueSafe)
+                return false;
+            overflowAlignmentKeyword = CSSValuePool::singleton().createIdentifierValue(value->id);
+        }
+    } else if (isAlignmentOverflowKeyword(value->id)) {
+        overflowAlignmentKeyword = CSSValuePool::singleton().createIdentifierValue(value->id);
+        value = m_valueList->next();
+        if (value && isItemPositionKeyword(value->id))
+            position = CSSValuePool::singleton().createIdentifierValue(value->id);
+        else
+            return false;
+    } else
+        return false;
+
+    if (m_valueList->next())
+        return false;
+
+    ASSERT(position);
+    if (overflowAlignmentKeyword)
+        addProperty(propId, createPrimitiveValuePair(position.release(), overflowAlignmentKeyword.release()), important);
     else
-        lval = rval;
+        addProperty(propId, position.release(), important);
+
+    return true;
 }
 
-static bool parseBackgroundClip(CSSParserValue* parserValue, RefPtr<CSSValue>& cssValue)
+static bool parseBackgroundClip(CSSParserValue& parserValue, RefPtr<CSSValue>& cssValue)
 {
-    if (parserValue->id == CSSValueBorderBox || parserValue->id == CSSValuePaddingBox
-        || parserValue->id == CSSValueContentBox || parserValue->id == CSSValueWebkitText) {
-        cssValue = cssValuePool().createIdentifierValue(parserValue->id);
+    if (parserValue.id == CSSValueBorderBox || parserValue.id == CSSValuePaddingBox
+        || parserValue.id == CSSValueContentBox || parserValue.id == CSSValueWebkitText) {
+        cssValue = CSSValuePool::singleton().createIdentifierValue(parserValue.id);
         return true;
     }
     return false;
@@ -3166,6 +3520,93 @@ bool CSSParser::useLegacyBackgroundSizeShorthandBehavior() const
     return m_context.useLegacyBackgroundSizeShorthandBehavior;
 }
 
+#if ENABLE(CSS_SCROLL_SNAP)
+bool CSSParser::parseNonElementSnapPoints(CSSPropertyID propId, bool important)
+{
+    RefPtr<CSSValueList> values = CSSValueList::createSpaceSeparated();
+    while (CSSParserValue* value = m_valueList->current()) {
+        ValueWithCalculation valueWithCalculation(*value);
+        if (validateUnit(valueWithCalculation, FPercent | FLength))
+            values->append(createPrimitiveNumericValue(valueWithCalculation));
+        else if (value->unit == CSSParserValue::Function
+            && value->function->args
+            && value->function->args->size() == 1
+            && equalLettersIgnoringASCIICase(value->function->name, "repeat(")) {
+            ValueWithCalculation argumentWithCalculation(*value->function->args.get()->current());
+            if (validateUnit(argumentWithCalculation, FLength | FPercent | FNonNeg)) {
+                values->append(CSSValuePool::singleton().createValue(LengthRepeat::create(createPrimitiveNumericValue(argumentWithCalculation))));
+                m_valueList->next();
+                if (m_valueList->current())
+                    return false;
+                break;
+            }
+        } else
+            return false;
+        m_valueList->next();
+    }
+    if (values->length()) {
+        addProperty(propId, values.release(), important);
+        m_valueList->next();
+        return true;
+    }
+    return false;
+}
+
+bool CSSParser::parseScrollSnapPositions(RefPtr<CSSValue>& cssValueX, RefPtr<CSSValue>& cssValueY)
+{
+    cssValueX = parsePositionX(*m_valueList);
+    if (!cssValueX)
+        return false;
+
+    // Don't accept odd-length lists of positions (must always have an X and a Y):
+    if (!m_valueList->next())
+        return false;
+
+    cssValueY = parsePositionY(*m_valueList);
+    if (!cssValueY)
+        return false;
+
+    return true;
+}
+
+bool CSSParser::parseScrollSnapDestination(CSSPropertyID propId, bool important)
+{
+    RefPtr<CSSValueList> position = CSSValueList::createSpaceSeparated();
+    if (m_valueList->size() != 2)
+        return false;
+
+    RefPtr<CSSValue> cssValueX, cssValueY;
+    if (!parseScrollSnapPositions(cssValueX, cssValueY))
+        return false;
+
+    position->append(cssValueX.releaseNonNull());
+    position->append(cssValueY.releaseNonNull());
+    addProperty(propId, position, important);
+    m_valueList->next();
+    return true;
+}
+
+bool CSSParser::parseScrollSnapCoordinate(CSSPropertyID propId, bool important)
+{
+    RefPtr<CSSValueList> positions = CSSValueList::createSpaceSeparated();
+    while (m_valueList->current()) {
+        RefPtr<CSSValue> cssValueX, cssValueY;
+        if (!parseScrollSnapPositions(cssValueX, cssValueY))
+            return false;
+
+        positions->append(cssValueX.releaseNonNull());
+        positions->append(cssValueY.releaseNonNull());
+        m_valueList->next();
+    }
+
+    if (positions->length()) {
+        addProperty(propId, positions.release(), important);
+        return true;
+    }
+    return false;
+}
+#endif
+
 const int cMaxFillProperties = 9;
 
 bool CSSParser::parseFillShorthand(CSSPropertyID propId, const CSSPropertyID* properties, int numProperties, bool important)
@@ -3185,9 +3626,10 @@ bool CSSParser::parseFillShorthand(CSSPropertyID propId, const CSSPropertyID* pr
     int i;
     bool foundPositionCSSProperty = false;
 
+    auto& cssValuePool = CSSValuePool::singleton();
     while (m_valueList->current()) {
-        CSSParserValue* val = m_valueList->current();
-        if (val->unit == CSSParserValue::Operator && val->iValue == ',') {
+        CSSParserValue& currentValue = *m_valueList->current();
+        if (currentValue.unit == CSSParserValue::Operator && currentValue.iValue == ',') {
             // We hit the end.  Fill in all remaining values with the initial value.
             m_valueList->next();
             for (i = 0; i < numProperties; ++i) {
@@ -3197,14 +3639,14 @@ bool CSSParser::parseFillShorthand(CSSPropertyID propId, const CSSPropertyID* pr
                     return false;
 
                 if (!parsedProperty[i] && properties[i] != CSSPropertyBackgroundColor) {
-                    addFillValue(values[i], cssValuePool().createImplicitInitialValue());
+                    addFillValue(values[i], cssValuePool.createImplicitInitialValue());
                     if (properties[i] == CSSPropertyBackgroundPosition || properties[i] == CSSPropertyWebkitMaskPosition)
-                        addFillValue(positionYValue, cssValuePool().createImplicitInitialValue());
+                        addFillValue(positionYValue, cssValuePool.createImplicitInitialValue());
                     if (properties[i] == CSSPropertyBackgroundRepeat || properties[i] == CSSPropertyWebkitMaskRepeat)
-                        addFillValue(repeatYValue, cssValuePool().createImplicitInitialValue());
+                        addFillValue(repeatYValue, cssValuePool.createImplicitInitialValue());
                     if ((properties[i] == CSSPropertyBackgroundOrigin || properties[i] == CSSPropertyWebkitMaskOrigin) && !parsedProperty[i]) {
                         // If background-origin wasn't present, then reset background-clip also.
-                        addFillValue(clipValue, cssValuePool().createImplicitInitialValue());
+                        addFillValue(clipValue, cssValuePool.createImplicitInitialValue());
                     }
                 }
                 parsedProperty[i] = false;
@@ -3214,7 +3656,7 @@ bool CSSParser::parseFillShorthand(CSSPropertyID propId, const CSSPropertyID* pr
         }
 
         bool sizeCSSPropertyExpected = false;
-        if (isForwardSlashOperator(val) && foundPositionCSSProperty) {
+        if (isForwardSlashOperator(currentValue) && foundPositionCSSProperty) {
             sizeCSSPropertyExpected = true;
             m_valueList->next();
         }
@@ -3232,26 +3674,24 @@ bool CSSParser::parseFillShorthand(CSSPropertyID propId, const CSSPropertyID* pr
                 RefPtr<CSSValue> val1;
                 RefPtr<CSSValue> val2;
                 CSSPropertyID propId1, propId2;
-                CSSParserValue* parserValue = m_valueList->current();
+                CSSParserValue& parserValue = *m_valueList->current();
+
                 if (parseFillProperty(properties[i], propId1, propId2, val1, val2)) {
                     parsedProperty[i] = found = true;
-                    addFillValue(values[i], val1.release());
+                    addFillValue(values[i], val1.releaseNonNull());
                     if (properties[i] == CSSPropertyBackgroundPosition || properties[i] == CSSPropertyWebkitMaskPosition)
-                        addFillValue(positionYValue, val2.release());
+                        addFillValue(positionYValue, val2.releaseNonNull());
                     if (properties[i] == CSSPropertyBackgroundRepeat || properties[i] == CSSPropertyWebkitMaskRepeat)
-                        addFillValue(repeatYValue, val2.release());
+                        addFillValue(repeatYValue, val2.releaseNonNull());
                     if (properties[i] == CSSPropertyBackgroundOrigin || properties[i] == CSSPropertyWebkitMaskOrigin) {
                         // Reparse the value as a clip, and see if we succeed.
                         if (parseBackgroundClip(parserValue, val1))
-                            addFillValue(clipValue, val1.release()); // The property parsed successfully.
+                            addFillValue(clipValue, val1.releaseNonNull()); // The property parsed successfully.
                         else
-                            addFillValue(clipValue, cssValuePool().createImplicitInitialValue()); // Some value was used for origin that is not supported by clip. Just reset clip instead.
+                            addFillValue(clipValue, cssValuePool.createImplicitInitialValue()); // Some value was used for origin that is not supported by clip. Just reset clip instead.
                     }
-                    if (properties[i] == CSSPropertyBackgroundClip || properties[i] == CSSPropertyWebkitMaskClip) {
-                        // Update clipValue
-                        addFillValue(clipValue, val1.release());
+                    if (properties[i] == CSSPropertyBackgroundClip || properties[i] == CSSPropertyWebkitMaskClip)
                         foundClip = true;
-                    }
                     if (properties[i] == CSSPropertyBackgroundPosition || properties[i] == CSSPropertyWebkitMaskPosition)
                         foundPositionCSSProperty = true;
                 }
@@ -3265,17 +3705,17 @@ bool CSSParser::parseFillShorthand(CSSPropertyID propId, const CSSPropertyID* pr
     }
 
     // Now add all of the properties we found.
-    for (i = 0; i < numProperties; i++) {
+    for (i = 0; i < numProperties; ++i) {
         // Fill in any remaining properties with the initial value.
         if (!parsedProperty[i]) {
-            addFillValue(values[i], cssValuePool().createImplicitInitialValue());
+            addFillValue(values[i], cssValuePool.createImplicitInitialValue());
             if (properties[i] == CSSPropertyBackgroundPosition || properties[i] == CSSPropertyWebkitMaskPosition)
-                addFillValue(positionYValue, cssValuePool().createImplicitInitialValue());
+                addFillValue(positionYValue, cssValuePool.createImplicitInitialValue());
             if (properties[i] == CSSPropertyBackgroundRepeat || properties[i] == CSSPropertyWebkitMaskRepeat)
-                addFillValue(repeatYValue, cssValuePool().createImplicitInitialValue());
+                addFillValue(repeatYValue, cssValuePool.createImplicitInitialValue());
             if (properties[i] == CSSPropertyBackgroundOrigin || properties[i] == CSSPropertyWebkitMaskOrigin) {
                 // If background-origin wasn't present, then reset background-clip also.
-                addFillValue(clipValue, cssValuePool().createImplicitInitialValue());
+                addFillValue(clipValue, cssValuePool.createImplicitInitialValue());
             }
         }
         if (properties[i] == CSSPropertyBackgroundPosition) {
@@ -3312,70 +3752,45 @@ bool CSSParser::parseFillShorthand(CSSPropertyID propId, const CSSPropertyID* pr
     return true;
 }
 
-#if ENABLE(CSS_VARIABLES)
-bool CSSParser::cssVariablesEnabled() const
+void CSSParser::addAnimationValue(RefPtr<CSSValue>& lval, Ref<CSSValue>&& rval)
 {
-    return m_context.isCSSVariablesEnabled;
-}
-
-void CSSParser::storeVariableDeclaration(const CSSParserString& name, PassOwnPtr<CSSParserValueList> value, bool important)
-{
-    // When CSSGrammar.y encounters an invalid declaration it passes null for the CSSParserValueList, just bail.
-    if (!value)
+    if (!lval) {
+        lval = WTFMove(rval);
         return;
-    
-    static const unsigned prefixLength = sizeof("-webkit-var-") - 1;
-    
-    ASSERT(name.length() > prefixLength);
-    AtomicString variableName = name.substring(prefixLength, name.length() - prefixLength);
-
-    StringBuilder builder;
-    for (unsigned i = 0, size = value->size(); i < size; i++) {
-        if (i)
-            builder.append(' ');
-        RefPtr<CSSValue> cssValue = value->valueAt(i)->createCSSValue();
-        if (!cssValue)
-            return;
-        builder.append(cssValue->cssText());
     }
-    addProperty(CSSPropertyVariable, CSSVariableValue::create(variableName, builder.toString().lower()), important, false);
-}
-#endif
 
-void CSSParser::addAnimationValue(RefPtr<CSSValue>& lval, PassRefPtr<CSSValue> rval)
-{
-    if (lval) {
-        if (lval->isValueList())
-            static_cast<CSSValueList*>(lval.get())->append(rval);
-        else {
-            PassRefPtr<CSSValue> oldVal(lval.release());
-            PassRefPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
-            list->append(oldVal);
-            list->append(rval);
-            lval = list;
-        }
+    if (is<CSSValueList>(*lval)) {
+        downcast<CSSValueList>(*lval).append(WTFMove(rval));
+        return;
     }
-    else
-        lval = rval;
+
+    auto list = CSSValueList::createCommaSeparated();
+    list.get().append(lval.releaseNonNull());
+    list.get().append(WTFMove(rval));
+    lval = WTFMove(list);
 }
 
-bool CSSParser::parseAnimationShorthand(bool important)
+bool CSSParser::parseAnimationShorthand(CSSPropertyID propId, bool important)
 {
-    const StylePropertyShorthand& animationProperties = webkitAnimationShorthandForParsing();
-    const unsigned numProperties = 7;
+    ASSERT(propId == CSSPropertyAnimation || propId == CSSPropertyWebkitAnimation);
+
+    const unsigned numProperties = 8;
+    const StylePropertyShorthand& shorthand = animationShorthandForParsing(propId);
 
     // The list of properties in the shorthand should be the same
     // length as the list with animation name in last position, even though they are
     // in a different order.
-    ASSERT(numProperties == webkitAnimationShorthandForParsing().length());
+    ASSERT(numProperties == shorthand.length());
+    ASSERT(numProperties == animationShorthand().length());
     ASSERT(numProperties == webkitAnimationShorthand().length());
 
-    ShorthandScope scope(this, CSSPropertyWebkitAnimation);
+    ShorthandScope scope(this, propId);
 
     bool parsedProperty[numProperties] = { false };
     AnimationParseContext context;
     RefPtr<CSSValue> values[numProperties];
 
+    auto& cssValuePool = CSSValuePool::singleton();
     unsigned i;
     while (m_valueList->current()) {
         CSSParserValue* val = m_valueList->current();
@@ -3384,7 +3799,7 @@ bool CSSParser::parseAnimationShorthand(bool important)
             m_valueList->next();
             for (i = 0; i < numProperties; ++i) {
                 if (!parsedProperty[i])
-                    addAnimationValue(values[i], cssValuePool().createImplicitInitialValue());
+                    addAnimationValue(values[i], cssValuePool.createImplicitInitialValue());
                 parsedProperty[i] = false;
             }
             if (!m_valueList->current())
@@ -3396,9 +3811,9 @@ bool CSSParser::parseAnimationShorthand(bool important)
         for (i = 0; i < numProperties; ++i) {
             if (!parsedProperty[i]) {
                 RefPtr<CSSValue> val;
-                if (parseAnimationProperty(animationProperties.properties()[i], val, context)) {
+                if (parseAnimationProperty(shorthand.properties()[i], val, context)) {
                     parsedProperty[i] = found = true;
-                    addAnimationValue(values[i], val.release());
+                    addAnimationValue(values[i], val.releaseNonNull());
                     break;
                 }
             }
@@ -3417,14 +3832,84 @@ bool CSSParser::parseAnimationShorthand(bool important)
     for (i = 0; i < numProperties; ++i) {
         // If we didn't find the property, set an intial value.
         if (!parsedProperty[i])
-            addAnimationValue(values[i], cssValuePool().createImplicitInitialValue());
+            addAnimationValue(values[i], cssValuePool.createImplicitInitialValue());
 
-        addProperty(animationProperties.properties()[i], values[i].release(), important);
+        addProperty(shorthand.properties()[i], values[i].release(), important);
     }
 
     return true;
 }
 
+RefPtr<CSSValue> CSSParser::parseColumnWidth()
+{
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    CSSValueID id = valueWithCalculation.value().id;
+    // Always parse this property in strict mode, since it would be ambiguous otherwise when used in the 'columns' shorthand property.
+    if (id != CSSValueAuto && !(validateUnit(valueWithCalculation, FLength | FNonNeg, CSSStrictMode) && parsedDouble(valueWithCalculation)))
+        return nullptr;
+
+    RefPtr<CSSValue> parsedValue = parseValidPrimitive(id, valueWithCalculation);
+    m_valueList->next();
+    return parsedValue;
+}
+
+RefPtr<CSSValue> CSSParser::parseColumnCount()
+{
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    CSSValueID id = valueWithCalculation.value().id;
+
+    if (id != CSSValueAuto && !validateUnit(valueWithCalculation, FPositiveInteger, CSSQuirksMode))
+        return nullptr;
+
+    RefPtr<CSSValue> parsedValue = parseValidPrimitive(id, valueWithCalculation);
+    m_valueList->next();
+    return parsedValue;
+}
+
+bool CSSParser::parseColumnsShorthand(bool important)
+{
+    RefPtr<CSSValue> columnWidth;
+    RefPtr<CSSValue> columnCount;
+    bool hasPendingExplicitAuto = false;
+
+    for (unsigned propertiesParsed = 0; CSSParserValue* value = m_valueList->current(); propertiesParsed++) {
+        if (propertiesParsed >= 2)
+            return false; // Too many values for this shorthand. Invalid declaration.
+        if (!propertiesParsed && value->id == CSSValueAuto) {
+            // 'auto' is a valid value for any of the two longhands, and at this point
+            // we don't know which one(s) it is meant for. We need to see if there are other values first.
+            m_valueList->next();
+            hasPendingExplicitAuto = true;
+        } else {
+            if (!columnWidth) {
+                if ((columnWidth = parseColumnWidth()))
+                    continue;
+            }
+            if (!columnCount) {
+                if ((columnCount = parseColumnCount()))
+                    continue;
+            }
+            // If we didn't find at least one match, this is an invalid shorthand and we have to ignore it.
+            return false;
+        }
+    }
+
+    // Any unassigned property at this point will become implicit 'auto'.
+    if (columnWidth)
+        addProperty(CSSPropertyColumnWidth, columnWidth, important);
+    else {
+        addProperty(CSSPropertyColumnWidth, CSSValuePool::singleton().createIdentifierValue(CSSValueAuto), important, !hasPendingExplicitAuto /* implicit */);
+        hasPendingExplicitAuto = false;
+    }
+
+    if (columnCount)
+        addProperty(CSSPropertyColumnCount, columnCount, important);
+    else
+        addProperty(CSSPropertyColumnCount, CSSValuePool::singleton().createIdentifierValue(CSSValueAuto), important, !hasPendingExplicitAuto /* implicit */);
+
+    return true;
+}
+
 bool CSSParser::parseTransitionShorthand(CSSPropertyID propId, bool important)
 {
     const unsigned numProperties = 4;
@@ -3437,6 +3922,7 @@ bool CSSParser::parseTransitionShorthand(CSSPropertyID propId, bool important)
     AnimationParseContext context;
     RefPtr<CSSValue> values[numProperties];
 
+    auto& cssValuePool = CSSValuePool::singleton();
     unsigned i;
     while (m_valueList->current()) {
         CSSParserValue* val = m_valueList->current();
@@ -3445,7 +3931,7 @@ bool CSSParser::parseTransitionShorthand(CSSPropertyID propId, bool important)
             m_valueList->next();
             for (i = 0; i < numProperties; ++i) {
                 if (!parsedProperty[i])
-                    addAnimationValue(values[i], cssValuePool().createImplicitInitialValue());
+                    addAnimationValue(values[i], cssValuePool.createImplicitInitialValue());
                 parsedProperty[i] = false;
             }
             if (!m_valueList->current())
@@ -3459,7 +3945,7 @@ bool CSSParser::parseTransitionShorthand(CSSPropertyID propId, bool important)
                 RefPtr<CSSValue> val;
                 if (parseAnimationProperty(shorthand.properties()[i], val, context)) {
                     parsedProperty[i] = found = true;
-                    addAnimationValue(values[i], val.release());
+                    addAnimationValue(values[i], val.releaseNonNull());
                 }
 
                 // There are more values to process but 'none' or 'all' were already defined as the animation property, the declaration becomes invalid.
@@ -3477,11 +3963,11 @@ bool CSSParser::parseTransitionShorthand(CSSPropertyID propId, bool important)
     // Fill in any remaining properties with the initial value.
     for (i = 0; i < numProperties; ++i) {
         if (!parsedProperty[i])
-            addAnimationValue(values[i], cssValuePool().createImplicitInitialValue());
+            addAnimationValue(values[i], cssValuePool.createImplicitInitialValue());
     }
 
     // Now add all of the properties we found.
-    for (i = 0; i < numProperties; i++)
+    for (i = 0; i < numProperties; ++i)
         addPropertyWithPrefixingVariant(shorthand.properties()[i], values[i].release(), important);
 
     return true;
@@ -3517,18 +4003,19 @@ bool CSSParser::parseShorthand(CSSPropertyID propId, const StylePropertyShorthan
         return true;
 
     // Fill in any remaining properties with the initial value.
-    ImplicitScope implicitScope(this, PropertyImplicit);
-    const StylePropertyShorthand* const* const propertiesForInitialization = shorthand.propertiesForInitialization();
+    auto& cssValuePool = CSSValuePool::singleton();
+    ImplicitScope implicitScope(*this, PropertyImplicit);
+    const StylePropertyShorthand* propertiesForInitialization = shorthand.propertiesForInitialization();
     for (unsigned i = 0; i < shorthand.length(); ++i) {
         if (propertyFound[i])
             continue;
 
         if (propertiesForInitialization) {
-            const StylePropertyShorthand& initProperties = *(propertiesForInitialization[i]);
+            const StylePropertyShorthand& initProperties = propertiesForInitialization[i];
             for (unsigned propIndex = 0; propIndex < initProperties.length(); ++propIndex)
-                addProperty(initProperties.properties()[propIndex], cssValuePool().createImplicitInitialValue(), important);
+                addProperty(initProperties.properties()[propIndex], cssValuePool.createImplicitInitialValue(), important);
         } else
-            addProperty(shorthand.properties()[i], cssValuePool().createImplicitInitialValue(), important);
+            addProperty(shorthand.properties()[i], cssValuePool.createImplicitInitialValue(), important);
     }
 
     return true;
@@ -3544,7 +4031,7 @@ bool CSSParser::parse4Values(CSSPropertyID propId, const CSSPropertyID *properti
      * right, bottom, and left, respectively.
      */
 
-    int num = inShorthand() ? 1 : m_valueList->size();
+    unsigned num = inShorthand() ? 1 : m_valueList->size();
 
     ShorthandScope scope(this, propId);
 
@@ -3554,7 +4041,7 @@ bool CSSParser::parse4Values(CSSPropertyID propId, const CSSPropertyID *properti
             if (!parseValue(properties[0], important))
                 return false;
             CSSValue* value = m_parsedProperties.last().value();
-            ImplicitScope implicitScope(this, PropertyImplicit);
+            ImplicitScope implicitScope(*this, PropertyImplicit);
             addProperty(properties[1], value, important);
             addProperty(properties[2], value, important);
             addProperty(properties[3], value, important);
@@ -3564,7 +4051,7 @@ bool CSSParser::parse4Values(CSSPropertyID propId, const CSSPropertyID *properti
             if (!parseValue(properties[0], important) || !parseValue(properties[1], important))
                 return false;
             CSSValue* value = m_parsedProperties[m_parsedProperties.size() - 2].value();
-            ImplicitScope implicitScope(this, PropertyImplicit);
+            ImplicitScope implicitScope(*this, PropertyImplicit);
             addProperty(properties[2], value, important);
             value = m_parsedProperties[m_parsedProperties.size() - 2].value();
             addProperty(properties[3], value, important);
@@ -3574,7 +4061,7 @@ bool CSSParser::parse4Values(CSSPropertyID propId, const CSSPropertyID *properti
             if (!parseValue(properties[0], important) || !parseValue(properties[1], important) || !parseValue(properties[2], important))
                 return false;
             CSSValue* value = m_parsedProperties[m_parsedProperties.size() - 2].value();
-            ImplicitScope implicitScope(this, PropertyImplicit);
+            ImplicitScope implicitScope(*this, PropertyImplicit);
             addProperty(properties[3], value, important);
             break;
         }
@@ -3605,10 +4092,10 @@ bool CSSParser::parsePage(CSSPropertyID propId, bool important)
         return false;
 
     if (value->id == CSSValueAuto) {
-        addProperty(propId, cssValuePool().createIdentifierValue(value->id), important);
+        addProperty(propId, CSSValuePool::singleton().createIdentifierValue(value->id), important);
         return true;
     } else if (value->id == 0 && value->unit == CSSPrimitiveValue::CSS_IDENT) {
-        addProperty(propId, createPrimitiveStringValue(value), important);
+        addProperty(propId, createPrimitiveStringValue(*value), important);
         return true;
     }
     return false;
@@ -3629,14 +4116,14 @@ bool CSSParser::parseSize(CSSPropertyID propId, bool important)
     RefPtr<CSSValueList> parsedValues = CSSValueList::createSpaceSeparated();
 
     // First parameter.
-    SizeParameterType paramType = parseSizeParameter(parsedValues.get(), value, None);
+    SizeParameterType paramType = parseSizeParameter(*parsedValues, *value, None);
     if (paramType == None)
         return false;
 
     // Second parameter, if any.
     value = m_valueList->next();
     if (value) {
-        paramType = parseSizeParameter(parsedValues.get(), value, paramType);
+        paramType = parseSizeParameter(*parsedValues, *value, paramType);
         if (paramType == None)
             return false;
     }
@@ -3645,19 +4132,19 @@ bool CSSParser::parseSize(CSSPropertyID propId, bool important)
     return true;
 }
 
-CSSParser::SizeParameterType CSSParser::parseSizeParameter(CSSValueList* parsedValues, CSSParserValue* value, SizeParameterType prevParamType)
+CSSParser::SizeParameterType CSSParser::parseSizeParameter(CSSValueList& parsedValues, CSSParserValue& value, SizeParameterType prevParamType)
 {
-    switch (value->id) {
+    switch (value.id) {
     case CSSValueAuto:
         if (prevParamType == None) {
-            parsedValues->append(cssValuePool().createIdentifierValue(value->id));
+            parsedValues.append(CSSValuePool::singleton().createIdentifierValue(value.id));
             return Auto;
         }
         return None;
     case CSSValueLandscape:
     case CSSValuePortrait:
         if (prevParamType == None || prevParamType == PageSize) {
-            parsedValues->append(cssValuePool().createIdentifierValue(value->id));
+            parsedValues.append(CSSValuePool::singleton().createIdentifierValue(value.id));
             return Orientation;
         }
         return None;
@@ -3672,16 +4159,18 @@ CSSParser::SizeParameterType CSSParser::parseSizeParameter(CSSValueList* parsedV
         if (prevParamType == None || prevParamType == Orientation) {
             // Normalize to Page Size then Orientation order by prepending.
             // This is not specified by the CSS3 Paged Media specification, but for simpler processing later (StyleResolver::applyPageSizeProperty).
-            parsedValues->prepend(cssValuePool().createIdentifierValue(value->id));
+            parsedValues.prepend(CSSValuePool::singleton().createIdentifierValue(value.id));
             return PageSize;
         }
         return None;
-    case 0:
-        if (validUnit(value, FLength | FNonNeg) && (prevParamType == None || prevParamType == Length)) {
-            parsedValues->append(createPrimitiveNumericValue(value));
+    case CSSValueInvalid: {
+        ValueWithCalculation valueWithCalculation(value);
+        if (validateUnit(valueWithCalculation, FLength | FNonNeg) && (prevParamType == None || prevParamType == Length)) {
+            parsedValues.append(createPrimitiveNumericValue(valueWithCalculation));
             return Length;
         }
         return None;
+    }
     default:
         return None;
     }
@@ -3692,13 +4181,10 @@ CSSParser::SizeParameterType CSSParser::parseSizeParameter(CSSValueList* parsedV
 bool CSSParser::parseQuotes(CSSPropertyID propId, bool important)
 {
     RefPtr<CSSValueList> values = CSSValueList::createCommaSeparated();
-    while (CSSParserValue* val = m_valueList->current()) {
-        RefPtr<CSSValue> parsedValue;
-        if (val->unit == CSSPrimitiveValue::CSS_STRING)
-            parsedValue = CSSPrimitiveValue::create(val->string, CSSPrimitiveValue::CSS_STRING);
-        else
+    while (CSSParserValue* value = m_valueList->current()) {
+        if (value->unit != CSSPrimitiveValue::CSS_STRING)
             break;
-        values->append(parsedValue.release());
+        values->append(CSSPrimitiveValue::create(value->string, CSSPrimitiveValue::CSS_STRING));
         m_valueList->next();
     }
     if (values->length()) {
@@ -3709,6 +4195,57 @@ bool CSSParser::parseQuotes(CSSPropertyID propId, bool important)
     return false;
 }
 
+bool CSSParser::parseAlt(CSSPropertyID propID, bool important)
+{
+    CSSParserValue& currentValue = *m_valueList->current();
+    RefPtr<CSSValue> parsedValue;
+
+    if (currentValue.unit == CSSPrimitiveValue::CSS_STRING)
+        parsedValue = createPrimitiveStringValue(currentValue);
+    else if (currentValue.unit == CSSParserValue::Function) {
+        CSSParserValueList* args = currentValue.function->args.get();
+        if (!args)
+            return false;
+        if (equalLettersIgnoringASCIICase(currentValue.function->name, "attr("))
+            parsedValue = parseAttr(*args);
+    }
+    
+    if (parsedValue) {
+        addProperty(propID, parsedValue.release(), important);
+        m_valueList->next();
+        return true;
+    }
+
+    return false;
+}
+
+bool CSSParser::parseCustomPropertyDeclaration(bool important, CSSValueID id)
+{
+    if (m_customPropertyName.isEmpty() || !m_valueList)
+        return false;
+    
+    auto& cssValuePool = CSSValuePool::singleton();
+    RefPtr<CSSValue> value;
+    if (id == CSSValueInherit)
+        value = cssValuePool.createInheritedValue();
+    else if (id == CSSValueInitial)
+        value = cssValuePool.createExplicitInitialValue();
+    else if (id == CSSValueUnset)
+        value = cssValuePool.createUnsetValue();
+    else if (id == CSSValueRevert)
+        value = cssValuePool.createRevertValue();
+    else {
+        RefPtr<CSSValueList> valueList = CSSValueList::createFromParserValueList(*m_valueList);
+        if (m_valueList->containsVariables())
+            value = CSSVariableDependentValue::create(valueList, CSSPropertyCustom);
+        else
+            value = valueList;
+    }
+
+    addProperty(CSSPropertyCustom, CSSCustomPropertyValue::create(m_customPropertyName, value), important, false);
+    return true;
+}
+
 // [ <string> | <uri> | <counter> | attr(X) | open-quote | close-quote | no-open-quote | no-close-quote ]+ | inherit
 // in CSS 2.1 this got somewhat reduced:
 // [ <string> | attr(X) | open-quote | close-quote | no-open-quote | no-close-quote ]+ | inherit
@@ -3716,40 +4253,40 @@ bool CSSParser::parseContent(CSSPropertyID propId, bool important)
 {
     RefPtr<CSSValueList> values = CSSValueList::createCommaSeparated();
 
-    while (CSSParserValue* val = m_valueList->current()) {
+    while (CSSParserValue* value = m_valueList->current()) {
         RefPtr<CSSValue> parsedValue;
-        if (val->unit == CSSPrimitiveValue::CSS_URI) {
+        if (value->unit == CSSPrimitiveValue::CSS_URI) {
             // url
-            parsedValue = CSSImageValue::create(completeURL(val->string));
-        } else if (val->unit == CSSParserValue::Function) {
+            parsedValue = CSSImageValue::create(completeURL(value->string));
+        } else if (value->unit == CSSParserValue::Function) {
             // attr(X) | counter(X [,Y]) | counters(X, Y, [,Z]) | -webkit-gradient(...)
-            CSSParserValueList* args = val->function->args.get();
+            CSSParserValueList* args = value->function->args.get();
             if (!args)
                 return false;
-            if (equalIgnoringCase(val->function->name, "attr(")) {
-                parsedValue = parseAttr(args);
+            if (equalLettersIgnoringASCIICase(value->function->name, "attr(")) {
+                parsedValue = parseAttr(*args);
                 if (!parsedValue)
                     return false;
-            } else if (equalIgnoringCase(val->function->name, "counter(")) {
-                parsedValue = parseCounterContent(args, false);
+            } else if (equalLettersIgnoringASCIICase(value->function->name, "counter(")) {
+                parsedValue = parseCounterContent(*args, false);
                 if (!parsedValue)
                     return false;
-            } else if (equalIgnoringCase(val->function->name, "counters(")) {
-                parsedValue = parseCounterContent(args, true);
+            } else if (equalLettersIgnoringASCIICase(value->function->name, "counters(")) {
+                parsedValue = parseCounterContent(*args, true);
                 if (!parsedValue)
                     return false;
 #if ENABLE(CSS_IMAGE_SET)
-            } else if (equalIgnoringCase(val->function->name, "-webkit-image-set(")) {
+            } else if (equalLettersIgnoringASCIICase(value->function->name, "-webkit-image-set(")) {
                 parsedValue = parseImageSet();
                 if (!parsedValue)
                     return false;
 #endif
-            } else if (isGeneratedImageValue(val)) {
-                if (!parseGeneratedImage(m_valueList.get(), parsedValue))
+            } else if (isGeneratedImageValue(*value)) {
+                if (!parseGeneratedImage(*m_valueList, parsedValue))
                     return false;
             } else
                 return false;
-        } else if (val->unit == CSSPrimitiveValue::CSS_IDENT) {
+        } else if (value->unit == CSSPrimitiveValue::CSS_IDENT) {
             // open-quote
             // close-quote
             // no-open-quote
@@ -3758,23 +4295,24 @@ bool CSSParser::parseContent(CSSPropertyID propId, bool important)
             // FIXME: These are not yet implemented (http://bugs.webkit.org/show_bug.cgi?id=6503).
             // none
             // normal
-            switch (val->id) {
+            switch (value->id) {
             case CSSValueOpenQuote:
             case CSSValueCloseQuote:
             case CSSValueNoOpenQuote:
             case CSSValueNoCloseQuote:
             case CSSValueNone:
             case CSSValueNormal:
-                parsedValue = cssValuePool().createIdentifierValue(val->id);
+                parsedValue = CSSValuePool::singleton().createIdentifierValue(value->id);
+                break;
             default:
                 break;
             }
-        } else if (val->unit == CSSPrimitiveValue::CSS_STRING) {
-            parsedValue = createPrimitiveStringValue(val);
+        } else if (value->unit == CSSPrimitiveValue::CSS_STRING) {
+            parsedValue = createPrimitiveStringValue(*value);
         }
         if (!parsedValue)
             break;
-        values->append(parsedValue.release());
+        values->append(parsedValue.releaseNonNull());
         m_valueList->next();
     }
 
@@ -3787,54 +4325,56 @@ bool CSSParser::parseContent(CSSPropertyID propId, bool important)
     return false;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAttr(CSSParserValueList* args)
+RefPtr<CSSValue> CSSParser::parseAttr(CSSParserValueList& args)
 {
-    if (args->size() != 1)
-        return 0;
+    if (args.size() != 1)
+        return nullptr;
 
-    CSSParserValue* a = args->current();
+    CSSParserValue& argument = *args.current();
 
-    if (a->unit != CSSPrimitiveValue::CSS_IDENT)
-        return 0;
+    if (argument.unit != CSSPrimitiveValue::CSS_IDENT)
+        return nullptr;
+
+    ASSERT(argument.string.length());
 
-    String attrName = a->string;
     // CSS allows identifiers with "-" at the start, like "-webkit-mask-image".
     // But HTML attribute names can't have those characters, and we should not
     // even parse them inside attr().
-    if (attrName[0] == '-')
-        return 0;
+    if (argument.string[0] == '-')
+        return nullptr;
 
     if (m_context.isHTMLDocument)
-        attrName = attrName.lower();
+        argument.string.convertToASCIILowercaseInPlace();
 
-    return cssValuePool().createValue(attrName, CSSPrimitiveValue::CSS_ATTR);
+    // FIXME: Is there some small benefit to creating an AtomicString here instead of a String?
+    return CSSValuePool::singleton().createValue(String(argument.string), CSSPrimitiveValue::CSS_ATTR);
 }
 
-PassRefPtr<CSSValue> CSSParser::parseBackgroundColor()
+RefPtr<CSSValue> CSSParser::parseBackgroundColor()
 {
     CSSValueID id = m_valueList->current()->id;
-    if (id == CSSValueWebkitText || (id >= CSSValueAqua && id <= CSSValueWindowtext) || id == CSSValueMenu || id == CSSValueCurrentcolor ||
-        (id >= CSSValueGrey && id < CSSValueWebkitText && inQuirksMode()))
-        return cssValuePool().createIdentifierValue(id);
+    if (id == CSSValueWebkitText || isValidSystemColorValue(id) || id == CSSValueMenu || id == CSSValueCurrentcolor
+        || (id >= CSSValueGrey && id < CSSValueWebkitText && inQuirksMode()))
+        return CSSValuePool::singleton().createIdentifierValue(id);
     return parseColor();
 }
 
-bool CSSParser::parseFillImage(CSSParserValueList* valueList, RefPtr<CSSValue>& value)
+bool CSSParser::parseFillImage(CSSParserValueList& valueList, RefPtr<CSSValue>& value)
 {
-    if (valueList->current()->id == CSSValueNone) {
-        value = cssValuePool().createIdentifierValue(CSSValueNone);
+    if (valueList.current()->id == CSSValueNone) {
+        value = CSSValuePool::singleton().createIdentifierValue(CSSValueNone);
         return true;
     }
-    if (valueList->current()->unit == CSSPrimitiveValue::CSS_URI) {
-        value = CSSImageValue::create(completeURL(valueList->current()->string));
+    if (valueList.current()->unit == CSSPrimitiveValue::CSS_URI) {
+        value = CSSImageValue::create(completeURL(valueList.current()->string));
         return true;
     }
 
-    if (isGeneratedImageValue(valueList->current()))
+    if (isGeneratedImageValue(*valueList.current()))
         return parseGeneratedImage(valueList, value);
     
 #if ENABLE(CSS_IMAGE_SET)
-    if (valueList->current()->unit == CSSParserValue::Function && equalIgnoringCase(valueList->current()->function->name, "-webkit-image-set(")) {
+    if (valueList.current()->unit == CSSParserValue::Function && equalLettersIgnoringASCIICase(valueList.current()->function->name, "-webkit-image-set(")) {
         value = parseImageSet();
         if (value)
             return true;
@@ -3844,46 +4384,48 @@ bool CSSParser::parseFillImage(CSSParserValueList* valueList, RefPtr<CSSValue>&
     return false;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseFillPositionX(CSSParserValueList* valueList)
+RefPtr<CSSPrimitiveValue> CSSParser::parsePositionX(CSSParserValueList& valueList)
 {
-    int id = valueList->current()->id;
+    int id = valueList.current()->id;
     if (id == CSSValueLeft || id == CSSValueRight || id == CSSValueCenter) {
         int percent = 0;
         if (id == CSSValueRight)
             percent = 100;
         else if (id == CSSValueCenter)
             percent = 50;
-        return cssValuePool().createValue(percent, CSSPrimitiveValue::CSS_PERCENTAGE);
+        return CSSValuePool::singleton().createValue(percent, CSSPrimitiveValue::CSS_PERCENTAGE);
     }
-    if (validUnit(valueList->current(), FPercent | FLength))
-        return createPrimitiveNumericValue(valueList->current());
-    return 0;
+    ValueWithCalculation valueWithCalculation(*valueList.current());
+    if (validateUnit(valueWithCalculation, FPercent | FLength))
+        return createPrimitiveNumericValue(valueWithCalculation);
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseFillPositionY(CSSParserValueList* valueList)
+RefPtr<CSSPrimitiveValue> CSSParser::parsePositionY(CSSParserValueList& valueList)
 {
-    int id = valueList->current()->id;
+    int id = valueList.current()->id;
     if (id == CSSValueTop || id == CSSValueBottom || id == CSSValueCenter) {
         int percent = 0;
         if (id == CSSValueBottom)
             percent = 100;
         else if (id == CSSValueCenter)
             percent = 50;
-        return cssValuePool().createValue(percent, CSSPrimitiveValue::CSS_PERCENTAGE);
+        return CSSValuePool::singleton().createValue(percent, CSSPrimitiveValue::CSS_PERCENTAGE);
     }
-    if (validUnit(valueList->current(), FPercent | FLength))
-        return createPrimitiveNumericValue(valueList->current());
-    return 0;
+    ValueWithCalculation valueWithCalculation(*valueList.current());
+    if (validateUnit(valueWithCalculation, FPercent | FLength))
+        return createPrimitiveNumericValue(valueWithCalculation);
+    return nullptr;
 }
 
-PassRefPtr<CSSPrimitiveValue> CSSParser::parseFillPositionComponent(CSSParserValueList* valueList, unsigned& cumulativeFlags, FillPositionFlag& individualFlag, FillPositionParsingMode parsingMode)
+RefPtr<CSSPrimitiveValue> CSSParser::parseFillPositionComponent(CSSParserValueList& valueList, unsigned& cumulativeFlags, FillPositionFlag& individualFlag, FillPositionParsingMode parsingMode)
 {
-    CSSValueID id = valueList->current()->id;
+    CSSValueID id = valueList.current()->id;
     if (id == CSSValueLeft || id == CSSValueTop || id == CSSValueRight || id == CSSValueBottom || id == CSSValueCenter) {
         int percent = 0;
         if (id == CSSValueLeft || id == CSSValueRight) {
             if (cumulativeFlags & XFillPosition)
-                return 0;
+                return nullptr;
             cumulativeFlags |= XFillPosition;
             individualFlag = XFillPosition;
             if (id == CSSValueRight)
@@ -3891,7 +4433,7 @@ PassRefPtr<CSSPrimitiveValue> CSSParser::parseFillPositionComponent(CSSParserVal
         }
         else if (id == CSSValueTop || id == CSSValueBottom) {
             if (cumulativeFlags & YFillPosition)
-                return 0;
+                return nullptr;
             cumulativeFlags |= YFillPosition;
             individualFlag = YFillPosition;
             if (id == CSSValueBottom)
@@ -3904,25 +4446,23 @@ PassRefPtr<CSSPrimitiveValue> CSSParser::parseFillPositionComponent(CSSParserVal
         }
 
         if (parsingMode == ResolveValuesAsKeyword)
-            return cssValuePool().createIdentifierValue(id);
+            return CSSValuePool::singleton().createIdentifierValue(id);
 
-        return cssValuePool().createValue(percent, CSSPrimitiveValue::CSS_PERCENTAGE);
+        return CSSValuePool::singleton().createValue(percent, CSSPrimitiveValue::CSS_PERCENTAGE);
     }
-    if (validUnit(valueList->current(), FPercent | FLength)) {
+    ValueWithCalculation valueWithCalculation(*valueList.current());
+    if (validateUnit(valueWithCalculation, FPercent | FLength)) {
         if (!cumulativeFlags) {
             cumulativeFlags |= XFillPosition;
             individualFlag = XFillPosition;
         } else if (cumulativeFlags & (XFillPosition | AmbiguousFillPosition)) {
             cumulativeFlags |= YFillPosition;
             individualFlag = YFillPosition;
-        } else {
-            if (m_parsedCalculation)
-                m_parsedCalculation.release();
-            return 0;
-        }
-        return createPrimitiveNumericValue(valueList->current());
+        } else
+            return nullptr;
+        return createPrimitiveNumericValue(valueWithCalculation);
     }
-    return 0;
+    return nullptr;
 }
 
 static bool isValueConflictingWithCurrentEdge(int value1, int value2)
@@ -3941,7 +4481,7 @@ static bool isFillPositionKeyword(CSSValueID value)
     return value == CSSValueLeft || value == CSSValueTop || value == CSSValueBottom || value == CSSValueRight || value == CSSValueCenter;
 }
 
-void CSSParser::parse4ValuesFillPosition(CSSParserValueList* valueList, RefPtr<CSSValue>& value1, RefPtr<CSSValue>& value2, PassRefPtr<CSSPrimitiveValue> parsedValue1, PassRefPtr<CSSPrimitiveValue> parsedValue2)
+void CSSParser::parse4ValuesFillPosition(CSSParserValueList& valueList, RefPtr<CSSPrimitiveValue>& value1, RefPtr<CSSPrimitiveValue>& value2, RefPtr<CSSPrimitiveValue>&& parsedValue1, RefPtr<CSSPrimitiveValue>&& parsedValue2)
 {
     // [ left | right ] [ <percentage] | <length> ] && [ top | bottom ] [ <percentage> | <length> ]
     // In the case of 4 values <position> requires the second value to be a length or a percentage.
@@ -3969,7 +4509,7 @@ void CSSParser::parse4ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
     if (isValueConflictingWithCurrentEdge(ident1, ident3))
         return;
 
-    valueList->next();
+    valueList.next();
 
     cumulativeFlags = 0;
     FillPositionFlag value4Flag = InvalidFillPosition;
@@ -3981,15 +4521,15 @@ void CSSParser::parse4ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
     if (isFillPositionKeyword(value4->getValueID()))
         return;
 
-    value1 = createPrimitiveValuePair(parsedValue1, parsedValue2);
-    value2 = createPrimitiveValuePair(value3, value4);
+    value1 = createPrimitiveValuePair(WTFMove(parsedValue1), WTFMove(parsedValue2));
+    value2 = createPrimitiveValuePair(value3.copyRef(), value4.copyRef());
 
     if (ident1 == CSSValueTop || ident1 == CSSValueBottom)
         value1.swap(value2);
 
-    valueList->next();
+    valueList.next();
 }
-void CSSParser::parse3ValuesFillPosition(CSSParserValueList* valueList, RefPtr<CSSValue>& value1, RefPtr<CSSValue>& value2, PassRefPtr<CSSPrimitiveValue> parsedValue1, PassRefPtr<CSSPrimitiveValue> parsedValue2)
+void CSSParser::parse3ValuesFillPosition(CSSParserValueList& valueList, RefPtr<CSSPrimitiveValue>& value1, RefPtr<CSSPrimitiveValue>& value2, RefPtr<CSSPrimitiveValue>&& parsedValue1, RefPtr<CSSPrimitiveValue>&& parsedValue2)
 {
     unsigned cumulativeFlags = 0;
     FillPositionFlag value3Flag = InvalidFillPosition;
@@ -3999,7 +4539,7 @@ void CSSParser::parse3ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
     if (!value3)
         return;
 
-    valueList->next();
+    valueList.next();
 
     bool swapNeeded = false;
     CSSValueID ident1 = parsedValue1->getValueID();
@@ -4009,6 +4549,7 @@ void CSSParser::parse3ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
     CSSValueID firstPositionKeyword;
     CSSValueID secondPositionKeyword;
 
+    auto& cssValuePool = CSSValuePool::singleton();
     if (ident1 == CSSValueCenter) {
         // <position> requires the first 'center' to be followed by a keyword.
         if (!isFillPositionKeyword(ident2))
@@ -4023,8 +4564,8 @@ void CSSParser::parse3ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
             firstPositionKeyword = CSSValueTop;
             swapNeeded = true;
         }
-        value1 = createPrimitiveValuePair(cssValuePool().createIdentifierValue(firstPositionKeyword), cssValuePool().createValue(50, CSSPrimitiveValue::CSS_PERCENTAGE));
-        value2 = createPrimitiveValuePair(parsedValue2, value3);
+        value1 = createPrimitiveValuePair(cssValuePool.createIdentifierValue(firstPositionKeyword), cssValuePool.createValue(50, CSSPrimitiveValue::CSS_PERCENTAGE));
+        value2 = createPrimitiveValuePair(WTFMove(parsedValue2), value3.copyRef());
     } else if (ident3 == CSSValueCenter) {
         if (isFillPositionKeyword(ident2))
             return;
@@ -4034,8 +4575,8 @@ void CSSParser::parse3ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
             secondPositionKeyword = CSSValueLeft;
             swapNeeded = true;
         }
-        value1 = createPrimitiveValuePair(parsedValue1, parsedValue2);
-        value2 = createPrimitiveValuePair(cssValuePool().createIdentifierValue(secondPositionKeyword), cssValuePool().createValue(50, CSSPrimitiveValue::CSS_PERCENTAGE));
+        value1 = createPrimitiveValuePair(WTFMove(parsedValue1), parsedValue2.copyRef());
+        value2 = createPrimitiveValuePair(cssValuePool.createIdentifierValue(secondPositionKeyword), cssValuePool.createValue(50, CSSPrimitiveValue::CSS_PERCENTAGE));
     } else {
         RefPtr<CSSPrimitiveValue> firstPositionValue;
         RefPtr<CSSPrimitiveValue> secondPositionValue;
@@ -4049,7 +4590,7 @@ void CSSParser::parse3ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
 
             secondPositionValue = value3;
             secondPositionKeyword = ident2;
-            firstPositionValue = cssValuePool().createValue(0, CSSPrimitiveValue::CSS_PERCENTAGE);
+            firstPositionValue = cssValuePool.createValue(0, CSSPrimitiveValue::CSS_PERCENTAGE);
         } else {
             // Per CSS, we should only accept: [ right | left | top | bottom ] [ <percentage> | <length> ] [ center | left | right | bottom | top ].
             if (!isFillPositionKeyword(ident3))
@@ -4057,40 +4598,43 @@ void CSSParser::parse3ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
 
             firstPositionValue = parsedValue2;
             secondPositionKeyword = ident3;
-            secondPositionValue = cssValuePool().createValue(0, CSSPrimitiveValue::CSS_PERCENTAGE);
+            secondPositionValue = cssValuePool.createValue(0, CSSPrimitiveValue::CSS_PERCENTAGE);
         }
 
         if (isValueConflictingWithCurrentEdge(ident1, secondPositionKeyword))
             return;
 
-        value1 = createPrimitiveValuePair(parsedValue1, firstPositionValue);
-        value2 = createPrimitiveValuePair(cssValuePool().createIdentifierValue(secondPositionKeyword), secondPositionValue);
+        value1 = createPrimitiveValuePair(WTFMove(parsedValue1), firstPositionValue.copyRef());
+        value2 = createPrimitiveValuePair(cssValuePool.createIdentifierValue(secondPositionKeyword), secondPositionValue.copyRef());
     }
 
     if (ident1 == CSSValueTop || ident1 == CSSValueBottom || swapNeeded)
         value1.swap(value2);
 
 #ifndef NDEBUG
-    CSSPrimitiveValue* first = static_cast<CSSPrimitiveValue*>(value1.get());
-    CSSPrimitiveValue* second = static_cast<CSSPrimitiveValue*>(value2.get());
-    ident1 = first->getPairValue()->first()->getValueID();
-    ident2 = second->getPairValue()->first()->getValueID();
+    CSSPrimitiveValue& first = *value1;
+    CSSPrimitiveValue& second = *value2;
+    ident1 = first.getPairValue()->first()->getValueID();
+    ident2 = second.getPairValue()->first()->getValueID();
     ASSERT(ident1 == CSSValueLeft || ident1 == CSSValueRight);
     ASSERT(ident2 == CSSValueBottom || ident2 == CSSValueTop);
 #endif
 }
 
-inline bool CSSParser::isPotentialPositionValue(CSSParserValue* value)
+inline bool CSSParser::isPotentialPositionValue(CSSParserValue& value)
 {
-    return isFillPositionKeyword(value->id) || validUnit(value, FPercent | FLength, ReleaseParsedCalcValue);
+    if (isFillPositionKeyword(value.id))
+        return true;
+    ValueWithCalculation valueWithCalculation(value);
+    return validateUnit(valueWithCalculation, FPercent | FLength);
 }
 
-void CSSParser::parseFillPosition(CSSParserValueList* valueList, RefPtr<CSSValue>& value1, RefPtr<CSSValue>& value2)
+void CSSParser::parseFillPosition(CSSParserValueList& valueList, RefPtr<CSSPrimitiveValue>& value1, RefPtr<CSSPrimitiveValue>& value2)
 {
     unsigned numberOfValues = 0;
-    for (unsigned i = valueList->currentIndex(); i < valueList->size(); ++i, ++numberOfValues) {
-        CSSParserValue* current = valueList->valueAt(i);
-        if (isComma(current) || !current || isForwardSlashOperator(current) || !isPotentialPositionValue(current))
+    for (unsigned i = valueList.currentIndex(); i < valueList.size(); ++i, ++numberOfValues) {
+        CSSParserValue* current = valueList.valueAt(i);
+        if (!current || isComma(current) || isForwardSlashOperator(*current) || !isPotentialPositionValue(*current))
             break;
     }
 
@@ -4105,7 +4649,7 @@ void CSSParser::parseFillPosition(CSSParserValueList* valueList, RefPtr<CSSValue
 
     ASSERT(numberOfValues > 2 && numberOfValues <= 4);
 
-    CSSParserValue* value = valueList->current();
+    CSSParserValue* value = valueList.current();
 
     // <position> requires the first value to be a background keyword.
     if (!isFillPositionKeyword(value->id))
@@ -4119,38 +4663,38 @@ void CSSParser::parseFillPosition(CSSParserValueList* valueList, RefPtr<CSSValue
     if (!value1)
         return;
 
-    value = valueList->next();
+    value = valueList.next();
 
     // In case we are parsing more than two values, relax the check inside of parseFillPositionComponent. top 20px is
     // a valid start for <position>.
     cumulativeFlags = AmbiguousFillPosition;
     value2 = parseFillPositionComponent(valueList, cumulativeFlags, value2Flag, ResolveValuesAsKeyword);
     if (value2)
-        valueList->next();
+        valueList.next();
     else {
-        value1.clear();
+        value1 = nullptr;
         return;
     }
 
-    RefPtr<CSSPrimitiveValue> parsedValue1 = static_cast<CSSPrimitiveValue*>(value1.get());
-    RefPtr<CSSPrimitiveValue> parsedValue2 = static_cast<CSSPrimitiveValue*>(value2.get());
+    RefPtr<CSSPrimitiveValue> parsedValue1 = value1;
+    RefPtr<CSSPrimitiveValue> parsedValue2 = value2;
 
-    value1.clear();
-    value2.clear();
+    value1 = nullptr;
+    value2 = nullptr;
 
     // Per CSS3 syntax, <position> can't have 'center' as its second keyword as we have more arguments to follow.
     if (parsedValue2->getValueID() == CSSValueCenter)
         return;
 
     if (numberOfValues == 3)
-        parse3ValuesFillPosition(valueList, value1, value2, parsedValue1.release(), parsedValue2.release());
+        parse3ValuesFillPosition(valueList, value1, value2, WTFMove(parsedValue1), WTFMove(parsedValue2));
     else
-        parse4ValuesFillPosition(valueList, value1, value2, parsedValue1.release(), parsedValue2.release());
+        parse4ValuesFillPosition(valueList, value1, value2, WTFMove(parsedValue1), WTFMove(parsedValue2));
 }
 
-void CSSParser::parse2ValuesFillPosition(CSSParserValueList* valueList, RefPtr<CSSValue>& value1, RefPtr<CSSValue>& value2)
+void CSSParser::parse2ValuesFillPosition(CSSParserValueList& valueList, RefPtr<CSSPrimitiveValue>& value1, RefPtr<CSSPrimitiveValue>& value2)
 {
-    CSSParserValue* value = valueList->current();
+    CSSParserValue* value = valueList.current();
 
     // Parse the first value.  We're just making sure that it is one of the valid keywords or a percentage/length.
     unsigned cumulativeFlags = 0;
@@ -4163,19 +4707,19 @@ void CSSParser::parse2ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
     // It only takes one value for background-position to be correctly parsed if it was specified in a shorthand (since we
     // can assume that any other values belong to the rest of the shorthand).  If we're not parsing a shorthand, though, the
     // value was explicitly specified for our property.
-    value = valueList->next();
+    value = valueList.next();
 
     // First check for the comma.  If so, we are finished parsing this value or value pair.
     if (isComma(value))
-        value = 0;
+        value = nullptr;
 
     if (value) {
         value2 = parseFillPositionComponent(valueList, cumulativeFlags, value2Flag);
         if (value2)
-            valueList->next();
+            valueList.next();
         else {
             if (!inShorthand()) {
-                value1.clear();
+                value1 = nullptr;
                 return;
             }
         }
@@ -4186,7 +4730,7 @@ void CSSParser::parse2ValuesFillPosition(CSSParserValueList* valueList, RefPtr<C
         // is simply 50%. This is our default.
         // For keywords, the keyword was either an x-keyword (left/right), a y-keyword (top/bottom), or an ambiguous keyword (center).
         // For left/right/center, the default of 50% in the y is still correct.
-        value2 = cssValuePool().createValue(50, CSSPrimitiveValue::CSS_PERCENTAGE);
+        value2 = CSSValuePool::singleton().createValue(50, CSSPrimitiveValue::CSS_PERCENTAGE);
 
     if (value1Flag == YFillPosition || value2Flag == XFillPosition)
         value1.swap(value2);
@@ -4197,22 +4741,22 @@ void CSSParser::parseFillRepeat(RefPtr<CSSValue>& value1, RefPtr<CSSValue>& valu
     CSSValueID id = m_valueList->current()->id;
     if (id == CSSValueRepeatX) {
         m_implicitShorthand = true;
-        value1 = cssValuePool().createIdentifierValue(CSSValueRepeat);
-        value2 = cssValuePool().createIdentifierValue(CSSValueNoRepeat);
+        value1 = CSSValuePool::singleton().createIdentifierValue(CSSValueRepeat);
+        value2 = CSSValuePool::singleton().createIdentifierValue(CSSValueNoRepeat);
         m_valueList->next();
         return;
     }
     if (id == CSSValueRepeatY) {
         m_implicitShorthand = true;
-        value1 = cssValuePool().createIdentifierValue(CSSValueNoRepeat);
-        value2 = cssValuePool().createIdentifierValue(CSSValueRepeat);
+        value1 = CSSValuePool::singleton().createIdentifierValue(CSSValueNoRepeat);
+        value2 = CSSValuePool::singleton().createIdentifierValue(CSSValueRepeat);
         m_valueList->next();
         return;
     }
     if (id == CSSValueRepeat || id == CSSValueNoRepeat || id == CSSValueRound || id == CSSValueSpace)
-        value1 = cssValuePool().createIdentifierValue(id);
+        value1 = CSSValuePool::singleton().createIdentifierValue(id);
     else {
-        value1 = 0;
+        value1 = nullptr;
         return;
     }
 
@@ -4222,7 +4766,7 @@ void CSSParser::parseFillRepeat(RefPtr<CSSValue>& value1, RefPtr<CSSValue>& valu
     if (value && !isComma(value)) {
         id = value->id;
         if (id == CSSValueRepeat || id == CSSValueNoRepeat || id == CSSValueRound || id == CSSValueSpace) {
-            value2 = cssValuePool().createIdentifierValue(id);
+            value2 = CSSValuePool::singleton().createIdentifierValue(id);
             m_valueList->next();
             return;
         }
@@ -4230,25 +4774,26 @@ void CSSParser::parseFillRepeat(RefPtr<CSSValue>& value1, RefPtr<CSSValue>& valu
 
     // If only one value was specified, value2 is the same as value1.
     m_implicitShorthand = true;
-    value2 = cssValuePool().createIdentifierValue(static_cast<CSSPrimitiveValue*>(value1.get())->getValueID());
+    value2 = CSSValuePool::singleton().createIdentifierValue(downcast<CSSPrimitiveValue>(*value1).getValueID());
 }
 
-PassRefPtr<CSSValue> CSSParser::parseFillSize(CSSPropertyID propId, bool& allowComma)
+RefPtr<CSSValue> CSSParser::parseFillSize(CSSPropertyID propId, bool& allowComma)
 {
     allowComma = true;
     CSSParserValue* value = m_valueList->current();
 
     if (value->id == CSSValueContain || value->id == CSSValueCover)
-        return cssValuePool().createIdentifierValue(value->id);
+        return CSSValuePool::singleton().createIdentifierValue(value->id);
 
     RefPtr<CSSPrimitiveValue> parsedValue1;
 
     if (value->id == CSSValueAuto)
-        parsedValue1 = cssValuePool().createIdentifierValue(CSSValueAuto);
+        parsedValue1 = CSSValuePool::singleton().createIdentifierValue(CSSValueAuto);
     else {
-        if (!validUnit(value, FLength | FPercent))
-            return 0;
-        parsedValue1 = createPrimitiveNumericValue(value);
+        ValueWithCalculation valueWithCalculation(*value);
+        if (!validateUnit(valueWithCalculation, FLength | FPercent))
+            return nullptr;
+        parsedValue1 = createPrimitiveNumericValue(valueWithCalculation);
     }
 
     RefPtr<CSSPrimitiveValue> parsedValue2;
@@ -4256,13 +4801,14 @@ PassRefPtr<CSSValue> CSSParser::parseFillSize(CSSPropertyID propId, bool& allowC
         if (value->unit == CSSParserValue::Operator && value->iValue == ',')
             allowComma = false;
         else if (value->id != CSSValueAuto) {
-            if (!validUnit(value, FLength | FPercent)) {
+            ValueWithCalculation valueWithCalculation(*value);
+            if (!validateUnit(valueWithCalculation, FLength | FPercent)) {
                 if (!inShorthand())
-                    return 0;
+                    return nullptr;
                 // We need to rewind the value list, so that when it is advanced we'll end up back at this value.
                 m_valueList->previous();
             } else
-                parsedValue2 = createPrimitiveNumericValue(value);
+                parsedValue2 = createPrimitiveNumericValue(valueWithCalculation);
         }
     } else if (!parsedValue2 && propId == CSSPropertyWebkitBackgroundSize) {
         // For backwards compatibility we set the second value to the first if it is omitted.
@@ -4273,7 +4819,7 @@ PassRefPtr<CSSValue> CSSParser::parseFillSize(CSSPropertyID propId, bool& allowC
 
     if (!parsedValue2)
         return parsedValue1;
-    return createPrimitiveValuePair(parsedValue1.release(), parsedValue2.release());
+    return createPrimitiveValuePair(WTFMove(parsedValue1), WTFMove(parsedValue2), propId == CSSPropertyWebkitBackgroundSize ? Pair::IdenticalValueEncoding::Coalesce : Pair::IdenticalValueEncoding::DoNotCoalesce);
 }
 
 bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1, CSSPropertyID& propId2,
@@ -4281,13 +4827,13 @@ bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1,
 {
     RefPtr<CSSValueList> values;
     RefPtr<CSSValueList> values2;
-    CSSParserValue* val;
+    CSSParserValue* currentValue;
     RefPtr<CSSValue> value;
     RefPtr<CSSValue> value2;
 
     bool allowComma = false;
 
-    retValue1 = retValue2 = 0;
+    retValue1 = retValue2 = nullptr;
     propId1 = propId;
     propId2 = propId;
     if (propId == CSSPropertyBackgroundPosition) {
@@ -4304,12 +4850,12 @@ bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1,
         propId2 = CSSPropertyWebkitMaskRepeatY;
     }
 
-    while ((val = m_valueList->current())) {
+    while ((currentValue = m_valueList->current())) {
         RefPtr<CSSValue> currValue;
         RefPtr<CSSValue> currValue2;
 
         if (allowComma) {
-            if (!isComma(val))
+            if (!isComma(currentValue))
                 return false;
             m_valueList->next();
             allowComma = false;
@@ -4322,14 +4868,14 @@ bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1,
                         m_valueList->next();
                     break;
                 case CSSPropertyBackgroundAttachment:
-                    if (val->id == CSSValueScroll || val->id == CSSValueFixed || val->id == CSSValueLocal) {
-                        currValue = cssValuePool().createIdentifierValue(val->id);
+                    if (currentValue->id == CSSValueScroll || currentValue->id == CSSValueFixed || currentValue->id == CSSValueLocal) {
+                        currValue = CSSValuePool::singleton().createIdentifierValue(currentValue->id);
                         m_valueList->next();
                     }
                     break;
                 case CSSPropertyBackgroundImage:
                 case CSSPropertyWebkitMaskImage:
-                    if (parseFillImage(m_valueList.get(), currValue))
+                    if (parseFillImage(*m_valueList, currValue))
                         m_valueList->next();
                     break;
                 case CSSPropertyWebkitBackgroundClip:
@@ -4338,58 +4884,62 @@ bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1,
                 case CSSPropertyWebkitMaskOrigin:
                     // The first three values here are deprecated and do not apply to the version of the property that has
                     // the -webkit- prefix removed.
-                    if (val->id == CSSValueBorder || val->id == CSSValuePadding || val->id == CSSValueContent ||
-                        val->id == CSSValueBorderBox || val->id == CSSValuePaddingBox || val->id == CSSValueContentBox ||
-                        ((propId == CSSPropertyWebkitBackgroundClip || propId == CSSPropertyWebkitMaskClip) &&
-                         (val->id == CSSValueText || val->id == CSSValueWebkitText))) {
-                        currValue = cssValuePool().createIdentifierValue(val->id);
+                    if (currentValue->id == CSSValueBorder || currentValue->id == CSSValuePadding || currentValue->id == CSSValueContent
+                        || currentValue->id == CSSValueBorderBox || currentValue->id == CSSValuePaddingBox || currentValue->id == CSSValueContentBox
+                        || ((propId == CSSPropertyWebkitBackgroundClip || propId == CSSPropertyWebkitMaskClip)
+                        && (currentValue->id == CSSValueText || currentValue->id == CSSValueWebkitText))) {
+                        currValue = CSSValuePool::singleton().createIdentifierValue(currentValue->id);
                         m_valueList->next();
                     }
                     break;
                 case CSSPropertyBackgroundClip:
-                    if (parseBackgroundClip(val, currValue))
+                    if (parseBackgroundClip(*currentValue, currValue))
                         m_valueList->next();
                     break;
                 case CSSPropertyBackgroundOrigin:
-                    if (val->id == CSSValueBorderBox || val->id == CSSValuePaddingBox || val->id == CSSValueContentBox) {
-                        currValue = cssValuePool().createIdentifierValue(val->id);
+                    if (currentValue->id == CSSValueBorderBox || currentValue->id == CSSValuePaddingBox || currentValue->id == CSSValueContentBox) {
+                        currValue = CSSValuePool::singleton().createIdentifierValue(currentValue->id);
                         m_valueList->next();
                     }
                     break;
                 case CSSPropertyBackgroundPosition:
-                case CSSPropertyWebkitMaskPosition:
-                    parseFillPosition(m_valueList.get(), currValue, currValue2);
+                case CSSPropertyWebkitMaskPosition: {
+                    RefPtr<CSSPrimitiveValue> value1;
+                    RefPtr<CSSPrimitiveValue> value2;
+                    parseFillPosition(*m_valueList, value1, value2);
+                    currValue = value1;
+                    currValue2 = value2;
                     // parseFillPosition advances the m_valueList pointer.
                     break;
+                }
                 case CSSPropertyBackgroundPositionX:
                 case CSSPropertyWebkitMaskPositionX: {
-                    currValue = parseFillPositionX(m_valueList.get());
+                    currValue = parsePositionX(*m_valueList);
                     if (currValue)
                         m_valueList->next();
                     break;
                 }
                 case CSSPropertyBackgroundPositionY:
                 case CSSPropertyWebkitMaskPositionY: {
-                    currValue = parseFillPositionY(m_valueList.get());
+                    currValue = parsePositionY(*m_valueList);
                     if (currValue)
                         m_valueList->next();
                     break;
                 }
                 case CSSPropertyWebkitBackgroundComposite:
                 case CSSPropertyWebkitMaskComposite:
-                    if (val->id >= CSSValueClear && val->id <= CSSValuePlusLighter) {
-                        currValue = cssValuePool().createIdentifierValue(val->id);
+                    if (currentValue->id >= CSSValueClear && currentValue->id <= CSSValuePlusLighter) {
+                        currValue = CSSValuePool::singleton().createIdentifierValue(currentValue->id);
                         m_valueList->next();
                     }
                     break;
-                case CSSPropertyWebkitBackgroundBlendMode:
-                    if (cssCompositingEnabled() && (val->id == CSSValueNormal || val->id == CSSValueMultiply
-                        || val->id == CSSValueScreen || val->id == CSSValueOverlay || val->id == CSSValueDarken
-                        || val->id == CSSValueLighten ||  val->id == CSSValueColorDodge || val->id == CSSValueColorBurn
-                        || val->id == CSSValueHardLight || val->id == CSSValueSoftLight || val->id == CSSValueDifference
-                        || val->id == CSSValueExclusion || val->id == CSSValueHue || val->id == CSSValueSaturation
-                        || val->id == CSSValueColor || val->id == CSSValueLuminosity)) {
-                        currValue = cssValuePool().createIdentifierValue(val->id);
+                case CSSPropertyBackgroundBlendMode:
+                    if (cssCompositingEnabled() && (currentValue->id == CSSValueNormal || currentValue->id == CSSValueMultiply
+                        || currentValue->id == CSSValueScreen || currentValue->id == CSSValueOverlay || currentValue->id == CSSValueDarken
+                        || currentValue->id == CSSValueLighten ||  currentValue->id == CSSValueColorDodge || currentValue->id == CSSValueColorBurn
+                        || currentValue->id == CSSValueHardLight || currentValue->id == CSSValueSoftLight || currentValue->id == CSSValueDifference
+                        || currentValue->id == CSSValueExclusion)) {
+                        currValue = CSSValuePool::singleton().createIdentifierValue(currentValue->id);
                         m_valueList->next();
                     }
                     break;
@@ -4406,6 +4956,14 @@ bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1,
                         m_valueList->next();
                     break;
                 }
+                case CSSPropertyWebkitMaskSourceType: {
+                    if (currentValue->id == CSSValueAuto || currentValue->id == CSSValueAlpha || currentValue->id == CSSValueLuminance) {
+                        currValue = CSSValuePool::singleton().createIdentifierValue(currentValue->id);
+                        m_valueList->next();
+                    } else
+                        currValue = nullptr;
+                    break;
+                }
                 default:
                     break;
             }
@@ -4414,21 +4972,21 @@ bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1,
 
             if (value && !values) {
                 values = CSSValueList::createCommaSeparated();
-                values->append(value.release());
+                values->append(value.releaseNonNull());
             }
 
             if (value2 && !values2) {
                 values2 = CSSValueList::createCommaSeparated();
-                values2->append(value2.release());
+                values2->append(value2.releaseNonNull());
             }
 
             if (values)
-                values->append(currValue.release());
+                values->append(currValue.releaseNonNull());
             else
                 value = currValue.release();
             if (currValue2) {
                 if (values2)
-                    values2->append(currValue2.release());
+                    values2->append(currValue2.releaseNonNull());
                 else
                     value2 = currValue2.release();
             }
@@ -4454,190 +5012,268 @@ bool CSSParser::parseFillProperty(CSSPropertyID propId, CSSPropertyID& propId1,
     return false;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationDelay()
+RefPtr<CSSValue> CSSParser::parseAnimationDelay()
 {
-    CSSParserValue* value = m_valueList->current();
-    if (validUnit(value, FTime))
-        return createPrimitiveNumericValue(value);
-    return 0;
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    if (validateUnit(valueWithCalculation, FTime))
+        return createPrimitiveNumericValue(valueWithCalculation);
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationDirection()
+RefPtr<CSSValue> CSSParser::parseAnimationDirection()
 {
     CSSParserValue* value = m_valueList->current();
     if (value->id == CSSValueNormal || value->id == CSSValueAlternate || value->id == CSSValueReverse || value->id == CSSValueAlternateReverse)
-        return cssValuePool().createIdentifierValue(value->id);
-    return 0;
+        return CSSValuePool::singleton().createIdentifierValue(value->id);
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationDuration()
+RefPtr<CSSValue> CSSParser::parseAnimationDuration()
 {
-    CSSParserValue* value = m_valueList->current();
-    if (validUnit(value, FTime | FNonNeg))
-        return createPrimitiveNumericValue(value);
-    return 0;
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    if (validateUnit(valueWithCalculation, FTime | FNonNeg))
+        return createPrimitiveNumericValue(valueWithCalculation);
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationFillMode()
+RefPtr<CSSValue> CSSParser::parseAnimationFillMode()
 {
     CSSParserValue* value = m_valueList->current();
     if (value->id == CSSValueNone || value->id == CSSValueForwards || value->id == CSSValueBackwards || value->id == CSSValueBoth)
-        return cssValuePool().createIdentifierValue(value->id);
-    return 0;
+        return CSSValuePool::singleton().createIdentifierValue(value->id);
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationIterationCount()
+RefPtr<CSSValue> CSSParser::parseAnimationIterationCount()
 {
-    CSSParserValue* value = m_valueList->current();
-    if (value->id == CSSValueInfinite)
-        return cssValuePool().createIdentifierValue(value->id);
-    if (validUnit(value, FNumber | FNonNeg))
-        return createPrimitiveNumericValue(value);
-    return 0;
+    CSSParserValue& value = *m_valueList->current();
+    if (value.id == CSSValueInfinite)
+        return CSSValuePool::singleton().createIdentifierValue(value.id);
+    ValueWithCalculation valueWithCalculation(value);
+    if (validateUnit(valueWithCalculation, FNumber | FNonNeg))
+        return createPrimitiveNumericValue(valueWithCalculation);
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationName()
+RefPtr<CSSValue> CSSParser::parseAnimationName()
 {
-    CSSParserValue* value = m_valueList->current();
-    if (value->unit == CSSPrimitiveValue::CSS_STRING || value->unit == CSSPrimitiveValue::CSS_IDENT) {
-        if (value->id == CSSValueNone || (value->unit == CSSPrimitiveValue::CSS_STRING && equalIgnoringCase(value, "none"))) {
-            return cssValuePool().createIdentifierValue(CSSValueNone);
-        } else {
-            return createPrimitiveStringValue(value);
+    CSSParserValue& value = *m_valueList->current();
+    if (value.unit == CSSPrimitiveValue::CSS_STRING || value.unit == CSSPrimitiveValue::CSS_IDENT) {
+        if (value.id == CSSValueNone || (value.unit == CSSPrimitiveValue::CSS_STRING && equalLettersIgnoringASCIICase(value, "none"))) {
+            return CSSValuePool::singleton().createIdentifierValue(CSSValueNone);
         }
+        return createPrimitiveStringValue(value);
     }
-    return 0;
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationPlayState()
+RefPtr<CSSValue> CSSParser::parseAnimationPlayState()
 {
-    CSSParserValue* value = m_valueList->current();
-    if (value->id == CSSValueRunning || value->id == CSSValuePaused)
-        return cssValuePool().createIdentifierValue(value->id);
-    return 0;
+    CSSParserValue& value = *m_valueList->current();
+    if (value.id == CSSValueRunning || value.id == CSSValuePaused)
+        return CSSValuePool::singleton().createIdentifierValue(value.id);
+    return nullptr;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationProperty(AnimationParseContext& context)
+#if ENABLE(CSS_ANIMATIONS_LEVEL_2)
+RefPtr<CSSValue> CSSParser::parseAnimationTrigger()
 {
     CSSParserValue* value = m_valueList->current();
-    if (value->unit != CSSPrimitiveValue::CSS_IDENT)
-        return 0;
-    CSSPropertyID result = cssPropertyID(value->string);
-    if (result)
-        return cssValuePool().createIdentifierValue(result);
-    if (equalIgnoringCase(value, "all")) {
+    if (value->id == CSSValueAuto)
+        return CSSValuePool::singleton().createIdentifierValue(CSSValueAuto);
+
+    if (value->unit != CSSParserValue::Function)
+        return nullptr;
+
+    CSSParserValueList* args = value->function->args.get();
+
+    if (equalLettersIgnoringASCIICase(value->function->name, "container-scroll(")) {
+        if (!args || (args->size() != 1 && args->size() != 3))
+            return nullptr;
+
+        CSSParserValue* argument = args->current();
+        ValueWithCalculation firstArgumentWithCalculation(*argument);
+        if (!validateUnit(firstArgumentWithCalculation, FLength))
+            return nullptr;
+
+        RefPtr<CSSValue> startValue = createPrimitiveNumericValue(firstArgumentWithCalculation);
+
+        argument = args->next();
+
+        if (!argument)
+            return CSSAnimationTriggerScrollValue::create(startValue.release());
+
+        if (!isComma(argument))
+            return nullptr;
+
+        argument = args->next();
+        ValueWithCalculation secondArgumentWithCalculation(*argument);
+        if (!validateUnit(secondArgumentWithCalculation, FLength))
+            return nullptr;
+
+        RefPtr<CSSValue> endValue = createPrimitiveNumericValue(secondArgumentWithCalculation);
+
+        return CSSAnimationTriggerScrollValue::create(startValue.release(), endValue.release());
+    }
+
+    return nullptr;
+}
+#endif
+
+RefPtr<CSSValue> CSSParser::parseAnimationProperty(AnimationParseContext& context)
+{
+    CSSParserValue& value = *m_valueList->current();
+    if (value.unit != CSSPrimitiveValue::CSS_IDENT)
+        return nullptr;
+    CSSPropertyID result = cssPropertyID(value.string);
+    if (result && result != CSSPropertyAll) // "all" value in animation is not equivalent to the all property.
+        return CSSValuePool::singleton().createIdentifierValue(result);
+    if (equalLettersIgnoringASCIICase(value, "all")) {
         context.sawAnimationPropertyKeyword();
-        return cssValuePool().createIdentifierValue(CSSValueAll);
+        return CSSValuePool::singleton().createIdentifierValue(CSSValueAll);
     }
-    if (equalIgnoringCase(value, "none")) {
+    if (equalLettersIgnoringASCIICase(value, "none")) {
         context.commitAnimationPropertyKeyword();
         context.sawAnimationPropertyKeyword();
-        return cssValuePool().createIdentifierValue(CSSValueNone);
+        return CSSValuePool::singleton().createIdentifierValue(CSSValueNone);
     }
-    return 0;
+    return nullptr;
 }
 
-bool CSSParser::parseTransformOriginShorthand(RefPtr<CSSValue>& value1, RefPtr<CSSValue>& value2, RefPtr<CSSValue>& value3)
+/* static */
+Vector<double> CSSParser::parseKeyframeSelector(const String& selector) {
+    Vector<double> keys;
+    Vector<String> strings;
+    selector.split(',', strings);
+
+    for (size_t i = 0; i < strings.size(); ++i) {
+        double key = -1;
+        String cur = strings[i].stripWhiteSpace();
+
+        // For now the syntax MUST be 'xxx%' or 'from' or 'to', where xxx is a legal floating point number
+        if (equalLettersIgnoringASCIICase(cur, "from"))
+            key = 0;
+        else if (equalLettersIgnoringASCIICase(cur, "to"))
+            key = 1;
+        else if (cur.endsWith('%')) {
+            double k = cur.substring(0, cur.length() - 1).toDouble();
+            if (k >= 0 && k <= 100)
+                key = k / 100;
+        }
+        if (key < 0) {
+            keys.clear();
+            break;
+        }
+        keys.append(key);
+    }
+
+    return keys;
+}
+
+bool CSSParser::parseTransformOriginShorthand(RefPtr<CSSPrimitiveValue>& value1, RefPtr<CSSPrimitiveValue>& value2, RefPtr<CSSValue>& value3)
 {
-    parse2ValuesFillPosition(m_valueList.get(), value1, value2);
+    parse2ValuesFillPosition(*m_valueList, value1, value2);
 
     // now get z
     if (m_valueList->current()) {
-        if (validUnit(m_valueList->current(), FLength)) {
-            value3 = createPrimitiveNumericValue(m_valueList->current());
+        ValueWithCalculation valueWithCalculation(*m_valueList->current());
+        if (validateUnit(valueWithCalculation, FLength)) {
+            value3 = createPrimitiveNumericValue(valueWithCalculation);
             m_valueList->next();
             return true;
         }
         return false;
     }
-    value3 = cssValuePool().createImplicitInitialValue();
+    value3 = CSSValuePool::singleton().createImplicitInitialValue();
     return true;
 }
 
-bool CSSParser::parseCubicBezierTimingFunctionValue(CSSParserValueList*& args, double& result)
+bool CSSParser::parseCubicBezierTimingFunctionValue(CSSParserValueList& args, double& result)
 {
-    CSSParserValue* v = args->current();
-    if (!validUnit(v, FNumber))
+    ValueWithCalculation argumentWithCalculation(*args.current());
+    if (!validateUnit(argumentWithCalculation, FNumber))
         return false;
-    result = v->fValue;
-    v = args->next();
-    if (!v)
+    result = parsedDouble(argumentWithCalculation);
+    CSSParserValue* nextValue = args.next();
+    if (!nextValue) {
         // The last number in the function has no comma after it, so we're done.
         return true;
-    if (!isComma(v))
+    }
+    if (!isComma(nextValue))
         return false;
-    args->next();
+    args.next();
     return true;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseAnimationTimingFunction()
+RefPtr<CSSValue> CSSParser::parseAnimationTimingFunction()
 {
-    CSSParserValue* value = m_valueList->current();
-    if (value->id == CSSValueEase || value->id == CSSValueLinear || value->id == CSSValueEaseIn || value->id == CSSValueEaseOut
-        || value->id == CSSValueEaseInOut || value->id == CSSValueStepStart || value->id == CSSValueStepEnd)
-        return cssValuePool().createIdentifierValue(value->id);
+    CSSParserValue& value = *m_valueList->current();
+    if (value.id == CSSValueEase || value.id == CSSValueLinear || value.id == CSSValueEaseIn || value.id == CSSValueEaseOut
+        || value.id == CSSValueEaseInOut || value.id == CSSValueStepStart || value.id == CSSValueStepEnd)
+        return CSSValuePool::singleton().createIdentifierValue(value.id);
 
     // We must be a function.
-    if (value->unit != CSSParserValue::Function)
-        return 0;
+    if (value.unit != CSSParserValue::Function)
+        return nullptr;
 
-    CSSParserValueList* args = value->function->args.get();
+    CSSParserValueList* args = value.function->args.get();
 
-    if (equalIgnoringCase(value->function->name, "steps(")) {
+    if (equalLettersIgnoringASCIICase(value.function->name, "steps(")) {
         // For steps, 1 or 2 params must be specified (comma-separated)
         if (!args || (args->size() != 1 && args->size() != 3))
-            return 0;
+            return nullptr;
 
         // There are two values.
         int numSteps;
         bool stepAtStart = false;
 
-        CSSParserValue* v = args->current();
-        if (!validUnit(v, FInteger))
-            return 0;
-        numSteps = clampToInteger(v->fValue);
+        CSSParserValue* argument = args->current();
+        ValueWithCalculation argumentWithCalculation(*argument);
+        if (!validateUnit(argumentWithCalculation, FInteger))
+            return nullptr;
+        numSteps = clampToInteger(parsedDouble(argumentWithCalculation));
         if (numSteps < 1)
-            return 0;
-        v = args->next();
+            return nullptr;
+        argument = args->next();
 
-        if (v) {
+        if (argument) {
             // There is a comma so we need to parse the second value
-            if (!isComma(v))
-                return 0;
-            v = args->next();
-            if (v->id != CSSValueStart && v->id != CSSValueEnd)
-                return 0;
-            stepAtStart = v->id == CSSValueStart;
+            if (!isComma(argument))
+                return nullptr;
+            argument = args->next();
+            if (argument->id != CSSValueStart && argument->id != CSSValueEnd)
+                return nullptr;
+            stepAtStart = argument->id == CSSValueStart;
         }
 
         return CSSStepsTimingFunctionValue::create(numSteps, stepAtStart);
     }
 
-    if (equalIgnoringCase(value->function->name, "cubic-bezier(")) {
+    if (equalLettersIgnoringASCIICase(value.function->name, "cubic-bezier(")) {
         // For cubic bezier, 4 values must be specified.
         if (!args || args->size() != 7)
-            return 0;
+            return nullptr;
 
         // There are two points specified. The x values must be between 0 and 1 but the y values can exceed this range.
         double x1, y1, x2, y2;
 
-        if (!parseCubicBezierTimingFunctionValue(args, x1))
-            return 0;
+        if (!parseCubicBezierTimingFunctionValue(*args, x1))
+            return nullptr;
         if (x1 < 0 || x1 > 1)
-            return 0;
-        if (!parseCubicBezierTimingFunctionValue(args, y1))
-            return 0;
-        if (!parseCubicBezierTimingFunctionValue(args, x2))
-            return 0;
+            return nullptr;
+        if (!parseCubicBezierTimingFunctionValue(*args, y1))
+            return nullptr;
+        if (!parseCubicBezierTimingFunctionValue(*args, x2))
+            return nullptr;
         if (x2 < 0 || x2 > 1)
-            return 0;
-        if (!parseCubicBezierTimingFunctionValue(args, y2))
-            return 0;
+            return nullptr;
+        if (!parseCubicBezierTimingFunctionValue(*args, y2))
+            return nullptr;
 
         return CSSCubicBezierTimingFunctionValue::create(x1, y1, x2, y2);
     }
 
-    return 0;
+    return nullptr;
 }
 
 bool CSSParser::parseAnimationProperty(CSSPropertyID propId, RefPtr<CSSValue>& result, AnimationParseContext& context)
@@ -4647,7 +5283,7 @@ bool CSSParser::parseAnimationProperty(CSSPropertyID propId, RefPtr<CSSValue>& r
     RefPtr<CSSValue> value;
     bool allowComma = false;
 
-    result = 0;
+    result = nullptr;
 
     while ((val = m_valueList->current())) {
         RefPtr<CSSValue> currValue;
@@ -4659,63 +5295,78 @@ bool CSSParser::parseAnimationProperty(CSSPropertyID propId, RefPtr<CSSValue>& r
         }
         else {
             switch (propId) {
-                case CSSPropertyWebkitAnimationDelay:
-                case CSSPropertyTransitionDelay:
-                case CSSPropertyWebkitTransitionDelay:
-                    currValue = parseAnimationDelay();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyWebkitAnimationDirection:
-                    currValue = parseAnimationDirection();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyWebkitAnimationDuration:
-                case CSSPropertyTransitionDuration:
-                case CSSPropertyWebkitTransitionDuration:
-                    currValue = parseAnimationDuration();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyWebkitAnimationFillMode:
-                    currValue = parseAnimationFillMode();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyWebkitAnimationIterationCount:
-                    currValue = parseAnimationIterationCount();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyWebkitAnimationName:
-                    currValue = parseAnimationName();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyWebkitAnimationPlayState:
-                    currValue = parseAnimationPlayState();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyTransitionProperty:
-                case CSSPropertyWebkitTransitionProperty:
-                    currValue = parseAnimationProperty(context);
-                    if (value && !context.animationPropertyKeywordAllowed())
-                        return false;
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                case CSSPropertyWebkitAnimationTimingFunction:
-                case CSSPropertyTransitionTimingFunction:
-                case CSSPropertyWebkitTransitionTimingFunction:
-                    currValue = parseAnimationTimingFunction();
-                    if (currValue)
-                        m_valueList->next();
-                    break;
-                default:
-                    ASSERT_NOT_REACHED();
+            case CSSPropertyAnimationDelay:
+            case CSSPropertyWebkitAnimationDelay:
+            case CSSPropertyTransitionDelay:
+            case CSSPropertyWebkitTransitionDelay:
+                currValue = parseAnimationDelay();
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyAnimationDirection:
+            case CSSPropertyWebkitAnimationDirection:
+                currValue = parseAnimationDirection();
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyAnimationDuration:
+            case CSSPropertyWebkitAnimationDuration:
+            case CSSPropertyTransitionDuration:
+            case CSSPropertyWebkitTransitionDuration:
+                currValue = parseAnimationDuration();
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyAnimationFillMode:
+            case CSSPropertyWebkitAnimationFillMode:
+                currValue = parseAnimationFillMode();
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyAnimationIterationCount:
+            case CSSPropertyWebkitAnimationIterationCount:
+                currValue = parseAnimationIterationCount();
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyAnimationName:
+            case CSSPropertyWebkitAnimationName:
+                currValue = parseAnimationName();
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyAnimationPlayState:
+            case CSSPropertyWebkitAnimationPlayState:
+                currValue = parseAnimationPlayState();
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyTransitionProperty:
+            case CSSPropertyWebkitTransitionProperty:
+                currValue = parseAnimationProperty(context);
+                if (value && !context.animationPropertyKeywordAllowed())
                     return false;
+                if (currValue)
+                    m_valueList->next();
+                break;
+            case CSSPropertyAnimationTimingFunction:
+            case CSSPropertyWebkitAnimationTimingFunction:
+            case CSSPropertyTransitionTimingFunction:
+            case CSSPropertyWebkitTransitionTimingFunction:
+                currValue = parseAnimationTimingFunction();
+                if (currValue)
+                    m_valueList->next();
+                break;
+#if ENABLE(CSS_ANIMATIONS_LEVEL_2)
+            case CSSPropertyWebkitAnimationTrigger:
+                currValue = parseAnimationTrigger();
+                if (currValue)
+                    m_valueList->next();
+                break;
+#endif
+            default:
+                ASSERT_NOT_REACHED();
+                return false;
             }
 
             if (!currValue)
@@ -4723,11 +5374,11 @@ bool CSSParser::parseAnimationProperty(CSSPropertyID propId, RefPtr<CSSValue>& r
 
             if (value && !values) {
                 values = CSSValueList::createCommaSeparated();
-                values->append(value.release());
+                values->append(value.releaseNonNull());
             }
 
             if (values)
-                values->append(currValue.release());
+                values->append(currValue.releaseNonNull());
             else
                 value = currValue.release();
 
@@ -4751,94 +5402,620 @@ bool CSSParser::parseAnimationProperty(CSSPropertyID propId, RefPtr<CSSValue>& r
     return false;
 }
 
+#if ENABLE(CSS_GRID_LAYOUT)
+static inline bool isValidGridPositionCustomIdent(const CSSParserValue& value)
+{
+    return value.unit == CSSPrimitiveValue::CSS_IDENT && value.id != CSSValueSpan && value.id != CSSValueAuto;
+}
+
+// The function parses [ <integer> || <custom-ident> ] in <grid-line> (which can be stand alone or with 'span').
+bool CSSParser::parseIntegerOrCustomIdentFromGridPosition(RefPtr<CSSPrimitiveValue>& numericValue, RefPtr<CSSPrimitiveValue>& gridLineName)
+{
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    if (validateUnit(valueWithCalculation, FInteger) && valueWithCalculation.value().fValue) {
+        numericValue = createPrimitiveNumericValue(valueWithCalculation);
+        CSSParserValue* nextValue = m_valueList->next();
+        if (nextValue && isValidGridPositionCustomIdent(*nextValue)) {
+            gridLineName = createPrimitiveStringValue(*nextValue);
+            m_valueList->next();
+        }
+        return true;
+    }
+
+    if (isValidGridPositionCustomIdent(valueWithCalculation)) {
+        gridLineName = createPrimitiveStringValue(valueWithCalculation);
+        if (CSSParserValue* nextValue = m_valueList->next()) {
+            ValueWithCalculation nextValueWithCalculation(*nextValue);
+            if (validateUnit(nextValueWithCalculation, FInteger) && nextValueWithCalculation.value().fValue) {
+                numericValue = createPrimitiveNumericValue(nextValueWithCalculation);
+                m_valueList->next();
+            }
+        }
+        return true;
+    }
+
+    return false;
+}
+
+RefPtr<CSSValue> CSSParser::parseGridPosition()
+{
+    CSSParserValue* value = m_valueList->current();
+    if (value->id == CSSValueAuto) {
+        m_valueList->next();
+        return CSSValuePool::singleton().createIdentifierValue(CSSValueAuto);
+    }
+
+    RefPtr<CSSPrimitiveValue> numericValue;
+    RefPtr<CSSPrimitiveValue> gridLineName;
+    bool hasSeenSpanKeyword = false;
+
+    if (value->id == CSSValueSpan) {
+        hasSeenSpanKeyword = true;
+        if (auto* nextValue = m_valueList->next()) {
+            if (!isForwardSlashOperator(*nextValue) && !parseIntegerOrCustomIdentFromGridPosition(numericValue, gridLineName))
+                return nullptr;
+        }
+    } else if (parseIntegerOrCustomIdentFromGridPosition(numericValue, gridLineName)) {
+        value = m_valueList->current();
+        if (value && value->id == CSSValueSpan) {
+            hasSeenSpanKeyword = true;
+            m_valueList->next();
+        }
+    }
+
+    // Check that we have consumed all the value list. For shorthands, the parser will pass
+    // the whole value list (including the opposite position).
+    if (m_valueList->current() && !isForwardSlashOperator(*m_valueList->current()))
+        return nullptr;
+
+    // If we didn't parse anything, this is not a valid grid position.
+    if (!hasSeenSpanKeyword && !gridLineName && !numericValue)
+        return nullptr;
+
+    // Negative numbers are not allowed for span (but are for <integer>).
+    if (hasSeenSpanKeyword && numericValue && numericValue->getIntValue() < 0)
+        return nullptr;
+
+    // For the <custom-ident> case.
+    if (gridLineName && !numericValue && !hasSeenSpanKeyword)
+        return CSSValuePool::singleton().createValue(gridLineName->getStringValue(), CSSPrimitiveValue::CSS_STRING);
+
+    RefPtr<CSSValueList> values = CSSValueList::createSpaceSeparated();
+    if (hasSeenSpanKeyword)
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueSpan));
+    if (numericValue)
+        values->append(numericValue.releaseNonNull());
+    if (gridLineName)
+        values->append(gridLineName.releaseNonNull());
+    ASSERT(values->length());
+    return values;
+}
+
+static RefPtr<CSSValue> gridMissingGridPositionValue(CSSValue& value)
+{
+    if (is<CSSPrimitiveValue>(value) && downcast<CSSPrimitiveValue>(value).isString())
+        return &value;
+
+    return CSSValuePool::singleton().createIdentifierValue(CSSValueAuto);
+}
+
 bool CSSParser::parseGridItemPositionShorthand(CSSPropertyID shorthandId, bool important)
 {
     ShorthandScope scope(this, shorthandId);
     const StylePropertyShorthand& shorthand = shorthandForProperty(shorthandId);
     ASSERT(shorthand.length() == 2);
-    if (!parseValue(shorthand.properties()[0], important))
+
+    RefPtr<CSSValue> startValue = parseGridPosition();
+    if (!startValue)
         return false;
 
-    if (!m_valueList->current()) {
-        // Only one value was specified, the opposite value should be set to 'auto'.
-        // FIXME: If the first property was <ident>, the opposite value should be the same <ident>.
-        addProperty(shorthand.properties()[1], cssValuePool().createIdentifierValue(CSSValueAuto), important);
+    RefPtr<CSSValue> endValue;
+    if (m_valueList->current()) {
+        if (!isForwardSlashOperator(*m_valueList->current()))
+            return false;
+
+        if (!m_valueList->next())
+            return false;
+
+        endValue = parseGridPosition();
+        if (!endValue || m_valueList->current())
+            return false;
+    } else
+        endValue = gridMissingGridPositionValue(*startValue);
+
+    addProperty(shorthand.properties()[0], startValue, important);
+    addProperty(shorthand.properties()[1], endValue, important);
+    return true;
+}
+
+bool CSSParser::parseGridGapShorthand(bool important)
+{
+    ShorthandScope scope(this, CSSPropertyWebkitGridGap);
+    ASSERT(shorthandForProperty(CSSPropertyWebkitGridGap).length() == 2);
+
+    CSSParserValue* value = m_valueList->current();
+    if (!value)
+        return false;
+
+    ValueWithCalculation columnValueWithCalculation(*value);
+    if (!validateUnit(columnValueWithCalculation, FLength | FNonNeg))
+        return false;
+
+    RefPtr<CSSPrimitiveValue> columnGap = createPrimitiveNumericValue(columnValueWithCalculation);
+
+    value = m_valueList->next();
+    if (!value) {
+        addProperty(CSSPropertyWebkitGridColumnGap, columnGap, important);
+        addProperty(CSSPropertyWebkitGridRowGap, columnGap, important);
         return true;
     }
 
-    if (!isForwardSlashOperator(m_valueList->current()))
+    ValueWithCalculation rowValueWithCalculation(*value);
+    if (!validateUnit(rowValueWithCalculation, FLength | FNonNeg))
         return false;
 
-    if (!m_valueList->next())
+    if (m_valueList->next())
         return false;
 
-    return parseValue(shorthand.properties()[1], important);
+    RefPtr<CSSPrimitiveValue> rowGap = createPrimitiveNumericValue(rowValueWithCalculation);
+
+    addProperty(CSSPropertyWebkitGridColumnGap, columnGap, important);
+    addProperty(CSSPropertyWebkitGridRowGap, rowGap, important);
+
+    return true;
 }
 
-bool CSSParser::parseGridTrackList(CSSPropertyID propId, bool important)
+bool CSSParser::parseGridTemplateRowsAndAreas(PassRefPtr<CSSValue> templateColumns, bool important)
 {
-    CSSParserValue* value = m_valueList->current();
-    if (value->id == CSSValueNone) {
-        if (m_valueList->next())
+    // At least template-areas strings must be defined.
+    if (!m_valueList->current())
+        return false;
+
+    NamedGridAreaMap gridAreaMap;
+    unsigned rowCount = 0;
+    unsigned columnCount = 0;
+    bool trailingIdentWasAdded = false;
+    RefPtr<CSSValueList> templateRows = CSSValueList::createSpaceSeparated();
+
+    do {
+        // Handle leading <custom-ident>*.
+        if (m_valueList->current()->unit == CSSParserValue::ValueList) {
+            if (trailingIdentWasAdded) {
+                // A row's trailing ident must be concatenated with the next row's leading one.
+                parseGridLineNames(*m_valueList, *templateRows, downcast<CSSGridLineNamesValue>(templateRows->item(templateRows->length() - 1)));
+            } else
+                parseGridLineNames(*m_valueList, *templateRows);
+        }
+
+        // Handle a template-area's row.
+        if (!parseGridTemplateAreasRow(gridAreaMap, rowCount, columnCount))
             return false;
+        ++rowCount;
+
+        // Handle template-rows's track-size.
+        if (m_valueList->current() && m_valueList->current()->unit != CSSParserValue::ValueList && m_valueList->current()->unit != CSSPrimitiveValue::CSS_STRING) {
+            RefPtr<CSSValue> value = parseGridTrackSize(*m_valueList);
+            if (!value)
+                return false;
+            templateRows->append(value.releaseNonNull());
+        } else
+            templateRows->append(CSSValuePool::singleton().createIdentifierValue(CSSValueAuto));
+
+        // This will handle the trailing/leading <custom-ident>* in the grammar.
+        trailingIdentWasAdded = false;
+        if (m_valueList->current() && m_valueList->current()->unit == CSSParserValue::ValueList)
+            trailingIdentWasAdded = parseGridLineNames(*m_valueList, *templateRows);
+    } while (m_valueList->current());
+
+    // [<track-list> /]?
+    if (templateColumns)
+        addProperty(CSSPropertyWebkitGridTemplateColumns, templateColumns, important);
+    else
+        addProperty(CSSPropertyWebkitGridTemplateColumns, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
+
+    // [<line-names>? <string> [<track-size> <line-names>]? ]+
+    RefPtr<CSSValue> templateAreas = CSSGridTemplateAreasValue::create(gridAreaMap, rowCount, columnCount);
+    addProperty(CSSPropertyWebkitGridTemplateAreas, templateAreas.release(), important);
+    addProperty(CSSPropertyWebkitGridTemplateRows, templateRows.release(), important);
+
+    return true;
+}
+
+bool CSSParser::parseGridTemplateShorthand(bool important)
+{
+    ShorthandScope scope(this, CSSPropertyWebkitGridTemplate);
+    ASSERT(shorthandForProperty(CSSPropertyWebkitGridTemplate).length() == 3);
+
+    // At least "none" must be defined.
+    if (!m_valueList->current())
+        return false;
+
+    bool firstValueIsNone = m_valueList->current()->id == CSSValueNone;
 
-        addProperty(propId, cssValuePool().createIdentifierValue(value->id), important);
+    // 1- 'none' case.
+    if (firstValueIsNone && !m_valueList->next()) {
+        addProperty(CSSPropertyWebkitGridTemplateColumns, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
+        addProperty(CSSPropertyWebkitGridTemplateRows, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
+        addProperty(CSSPropertyWebkitGridTemplateAreas, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
         return true;
     }
 
-    RefPtr<CSSValueList> values = CSSValueList::createSpaceSeparated();
-    while (m_valueList->current()) {
-        RefPtr<CSSPrimitiveValue> primitiveValue = parseGridTrackSize();
-        if (!primitiveValue)
+    unsigned index = 0;
+    RefPtr<CSSValue> columnsValue = firstValueIsNone ? CSSValuePool::singleton().createIdentifierValue(CSSValueNone) : parseGridTrackList();
+
+    // 2- <grid-template-columns> / <grid-template-columns> syntax.
+    if (columnsValue) {
+        if (!(m_valueList->current() && isForwardSlashOperator(*m_valueList->current()) && m_valueList->next()))
             return false;
+        index = m_valueList->currentIndex();
+        if (RefPtr<CSSValue> rowsValue = parseGridTrackList()) {
+            if (m_valueList->current())
+                return false;
+            addProperty(CSSPropertyWebkitGridTemplateColumns, columnsValue.release(), important);
+            addProperty(CSSPropertyWebkitGridTemplateRows, rowsValue.release(), important);
+            addProperty(CSSPropertyWebkitGridTemplateAreas, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
+            return true;
+        }
+    }
+
+
+    // 3- [<track-list> /]? [<line-names>? <string> [<track-size> <line-names>]? ]+ syntax.
+    // The template-columns <track-list> can't be 'none'.
+    if (firstValueIsNone)
+        return false;
+    // It requires to rewind parsing due to previous syntax failures.
+    m_valueList->setCurrentIndex(index);
+    return parseGridTemplateRowsAndAreas(columnsValue, important);
+}
 
-        values->append(primitiveValue.release());
+bool CSSParser::parseGridShorthand(bool important)
+{
+    ShorthandScope scope(this, CSSPropertyWebkitGrid);
+    ASSERT(shorthandForProperty(CSSPropertyWebkitGrid).length() == 8);
+
+    // 1- <grid-template>
+    if (parseGridTemplateShorthand(important)) {
+        // It can only be specified the explicit or the implicit grid properties in a single grid declaration.
+        // The sub-properties not specified are set to their initial value, as normal for shorthands.
+        addProperty(CSSPropertyWebkitGridAutoFlow, CSSValuePool::singleton().createImplicitInitialValue(), important);
+        addProperty(CSSPropertyWebkitGridAutoColumns, CSSValuePool::singleton().createImplicitInitialValue(), important);
+        addProperty(CSSPropertyWebkitGridAutoRows, CSSValuePool::singleton().createImplicitInitialValue(), important);
+        addProperty(CSSPropertyWebkitGridColumnGap, CSSValuePool::singleton().createImplicitInitialValue(), important);
+        addProperty(CSSPropertyWebkitGridRowGap, CSSValuePool::singleton().createImplicitInitialValue(), important);
+        return true;
     }
-    addProperty(propId, values.release(), important);
+
+    // Need to rewind parsing to explore the alternative syntax of this shorthand.
+    m_valueList->setCurrentIndex(0);
+
+    // 2- <grid-auto-flow> [ <grid-auto-columns> [ / <grid-auto-rows> ]? ]
+    if (!parseValue(CSSPropertyWebkitGridAutoFlow, important))
+        return false;
+
+    RefPtr<CSSValue> autoColumnsValue;
+    RefPtr<CSSValue> autoRowsValue;
+
+    if (m_valueList->current()) {
+        autoColumnsValue = parseGridTrackSize(*m_valueList);
+        if (!autoColumnsValue)
+            return false;
+        if (m_valueList->current()) {
+            if (!isForwardSlashOperator(*m_valueList->current()) || !m_valueList->next())
+                return false;
+            autoRowsValue = parseGridTrackSize(*m_valueList);
+            if (!autoRowsValue)
+                return false;
+        }
+        if (m_valueList->current())
+            return false;
+    } else {
+        // Other omitted values are set to their initial values.
+        autoColumnsValue = CSSValuePool::singleton().createImplicitInitialValue();
+        autoRowsValue = CSSValuePool::singleton().createImplicitInitialValue();
+    }
+
+    // if <grid-auto-rows> value is omitted, it is set to the value specified for grid-auto-columns.
+    if (!autoRowsValue)
+        autoRowsValue = autoColumnsValue;
+
+    addProperty(CSSPropertyWebkitGridAutoColumns, autoColumnsValue.release(), important);
+    addProperty(CSSPropertyWebkitGridAutoRows, autoRowsValue.release(), important);
+
+    // It can only be specified the explicit or the implicit grid properties in a single grid declaration.
+    // The sub-properties not specified are set to their initial value, as normal for shorthands.
+    addProperty(CSSPropertyWebkitGridTemplateColumns, CSSValuePool::singleton().createImplicitInitialValue(), important);
+    addProperty(CSSPropertyWebkitGridTemplateRows, CSSValuePool::singleton().createImplicitInitialValue(), important);
+    addProperty(CSSPropertyWebkitGridTemplateAreas, CSSValuePool::singleton().createImplicitInitialValue(), important);
+    addProperty(CSSPropertyWebkitGridColumnGap, CSSValuePool::singleton().createImplicitInitialValue(), important);
+    addProperty(CSSPropertyWebkitGridRowGap, CSSValuePool::singleton().createImplicitInitialValue(), important);
+
     return true;
 }
 
-PassRefPtr<CSSPrimitiveValue> CSSParser::parseGridTrackSize()
+bool CSSParser::parseGridAreaShorthand(bool important)
 {
-    CSSParserValue* currentValue = m_valueList->current();
+    ShorthandScope scope(this, CSSPropertyWebkitGridArea);
+    ASSERT(shorthandForProperty(CSSPropertyWebkitGridArea).length() == 4);
+
+    RefPtr<CSSValue> rowStartValue = parseGridPosition();
+    if (!rowStartValue)
+        return false;
+
+    RefPtr<CSSValue> columnStartValue;
+    if (!parseSingleGridAreaLonghand(columnStartValue))
+        return false;
+
+    RefPtr<CSSValue> rowEndValue;
+    if (!parseSingleGridAreaLonghand(rowEndValue))
+        return false;
+
+    RefPtr<CSSValue> columnEndValue;
+    if (!parseSingleGridAreaLonghand(columnEndValue))
+        return false;
+
+    if (!columnStartValue)
+        columnStartValue = gridMissingGridPositionValue(*rowStartValue);
+
+    if (!rowEndValue)
+        rowEndValue = gridMissingGridPositionValue(*rowStartValue);
+
+    if (!columnEndValue)
+        columnEndValue = gridMissingGridPositionValue(*columnStartValue);
+
+    addProperty(CSSPropertyWebkitGridRowStart, rowStartValue, important);
+    addProperty(CSSPropertyWebkitGridColumnStart, columnStartValue, important);
+    addProperty(CSSPropertyWebkitGridRowEnd, rowEndValue, important);
+    addProperty(CSSPropertyWebkitGridColumnEnd, columnEndValue, important);
+    return true;
+}
+
+bool CSSParser::parseSingleGridAreaLonghand(RefPtr<CSSValue>& property)
+{
+    if (!m_valueList->current())
+        return true;
+
+    if (!isForwardSlashOperator(*m_valueList->current()))
+        return false;
+
+    if (!m_valueList->next())
+        return false;
+
+    property = parseGridPosition();
+    return true;
+}
+
+bool CSSParser::parseGridLineNames(CSSParserValueList& inputList, CSSValueList& valueList, CSSGridLineNamesValue* previousNamedAreaTrailingLineNames)
+{
+    ASSERT(inputList.current() && inputList.current()->unit == CSSParserValue::ValueList);
+
+    CSSParserValueList& identList = *inputList.current()->valueList;
+    if (!identList.size()) {
+        inputList.next();
+        return false;
+    }
+
+    // Need to ensure the identList is at the heading index, since the parserList might have been rewound.
+    identList.setCurrentIndex(0);
+    RefPtr<CSSGridLineNamesValue> lineNames;
+    if (previousNamedAreaTrailingLineNames)
+        lineNames = previousNamedAreaTrailingLineNames;
+    else
+        lineNames = CSSGridLineNamesValue::create();
+    while (CSSParserValue* identValue = identList.current()) {
+        ASSERT(identValue->unit == CSSPrimitiveValue::CSS_IDENT);
+        lineNames->append(createPrimitiveStringValue(*identValue));
+        identList.next();
+    }
+    if (!previousNamedAreaTrailingLineNames)
+        valueList.append(lineNames.releaseNonNull());
+
+    inputList.next();
+    return true;
+}
+
+RefPtr<CSSValue> CSSParser::parseGridTrackList()
+{
+    CSSParserValue* value = m_valueList->current();
+    if (value->id == CSSValueNone) {
+        m_valueList->next();
+        return CSSValuePool::singleton().createIdentifierValue(CSSValueNone);
+    }
+
+    RefPtr<CSSValueList> values = CSSValueList::createSpaceSeparated();
+    // Handle leading  <custom-ident>*.
+    value = m_valueList->current();
+    if (value && value->unit == CSSParserValue::ValueList)
+        parseGridLineNames(*m_valueList, *values);
+
+    bool seenTrackSizeOrRepeatFunction = false;
+    while (CSSParserValue* currentValue = m_valueList->current()) {
+        if (isForwardSlashOperator(*currentValue))
+            break;
+        if (currentValue->unit == CSSParserValue::Function && equalLettersIgnoringASCIICase(currentValue->function->name, "repeat(")) {
+            if (!parseGridTrackRepeatFunction(*values))
+                return nullptr;
+        } else {
+            RefPtr<CSSValue> value = parseGridTrackSize(*m_valueList);
+            if (!value)
+                return nullptr;
+            values->append(value.releaseNonNull());
+        }
+        seenTrackSizeOrRepeatFunction = true;
+
+        // This will handle the trailing <custom-ident>* in the grammar.
+        value = m_valueList->current();
+        if (value && value->unit == CSSParserValue::ValueList)
+            parseGridLineNames(*m_valueList, *values);
+    }
+
+    if (!seenTrackSizeOrRepeatFunction)
+        return nullptr;
+
+    return values;
+}
+
+bool CSSParser::parseGridTrackRepeatFunction(CSSValueList& list)
+{
+    CSSParserValueList* arguments = m_valueList->current()->function->args.get();
+    if (!arguments || arguments->size() < 3)
+        return false;
+
+    ValueWithCalculation firstValueWithCalculation(*arguments->valueAt(0));
+    if (!validateUnit(firstValueWithCalculation, FPositiveInteger) || !isComma(arguments->valueAt(1)))
+        return false;
+
+    // If arguments->valueAt(0)->fValue > SIZE_MAX then repetitions becomes 0 during the type casting, that's why we
+    // clamp it down to kGridMaxTracks before the type casting.
+    unsigned repetitions = clampTo<unsigned>(parsedDouble(firstValueWithCalculation), 0, kGridMaxTracks);
+
+    RefPtr<CSSValueList> repeatedValues = CSSValueList::createSpaceSeparated();
+    arguments->next(); // Skip the repetition count.
+    arguments->next(); // Skip the comma.
+
+    // Handle leading <custom-ident>*.
+    CSSParserValue* currentValue = arguments->current();
+    if (currentValue && currentValue->unit == CSSParserValue::ValueList)
+        parseGridLineNames(*arguments, *repeatedValues);
+
+    unsigned numberOfTracks = 0;
+    while (arguments->current()) {
+        RefPtr<CSSValue> trackSize = parseGridTrackSize(*arguments);
+        if (!trackSize)
+            return false;
+
+        repeatedValues->append(trackSize.releaseNonNull());
+        ++numberOfTracks;
+
+        // This takes care of any trailing <custom-ident>* in the grammar.
+        currentValue = arguments->current();
+        if (currentValue && currentValue->unit == CSSParserValue::ValueList)
+            parseGridLineNames(*arguments, *repeatedValues);
+    }
+
+    // We should have found at least one <track-size>, otherwise the declaration is invalid.
+    if (!numberOfTracks)
+        return false;
+
+    // We clamp the number of repetitions to a multiple of the repeat() track list's size, while staying below the max
+    // grid size.
+    repetitions = std::min(repetitions, kGridMaxTracks / numberOfTracks);
+
+    for (size_t i = 0; i < repetitions; ++i) {
+        for (size_t j = 0; j < repeatedValues->length(); ++j)
+            list.append(*repeatedValues->itemWithoutBoundsCheck(j));
+    }
+
     m_valueList->next();
+    return true;
+}
 
-    if (currentValue->id == CSSValueAuto)
-        return cssValuePool().createIdentifierValue(CSSValueAuto);
+RefPtr<CSSValue> CSSParser::parseGridTrackSize(CSSParserValueList& inputList)
+{
+    CSSParserValue& currentValue = *inputList.current();
+    inputList.next();
+
+    if (currentValue.id == CSSValueAuto)
+        return CSSValuePool::singleton().createIdentifierValue(CSSValueAuto);
 
-    if (currentValue->unit == CSSParserValue::Function && equalIgnoringCase(currentValue->function->name, "minmax(")) {
+    if (currentValue.unit == CSSParserValue::Function && equalLettersIgnoringASCIICase(currentValue.function->name, "minmax(")) {
         // The spec defines the following grammar: minmax( <track-breadth> , <track-breadth> )
-        CSSParserValueList* arguments = currentValue->function->args.get();
+        CSSParserValueList* arguments = currentValue.function->args.get();
         if (!arguments || arguments->size() != 3 || !isComma(arguments->valueAt(1)))
-            return 0;
+            return nullptr;
 
-        RefPtr<CSSPrimitiveValue> minTrackBreadth = parseGridBreadth(arguments->valueAt(0));
+        RefPtr<CSSPrimitiveValue> minTrackBreadth = parseGridBreadth(*arguments->valueAt(0));
         if (!minTrackBreadth)
-            return 0;
+            return nullptr;
 
-        RefPtr<CSSPrimitiveValue> maxTrackBreadth = parseGridBreadth(arguments->valueAt(2));
+        RefPtr<CSSPrimitiveValue> maxTrackBreadth = parseGridBreadth(*arguments->valueAt(2));
         if (!maxTrackBreadth)
-            return 0;
+            return nullptr;
+
+        RefPtr<CSSValueList> parsedArguments = CSSValueList::createCommaSeparated();
+        parsedArguments->append(minTrackBreadth.releaseNonNull());
+        parsedArguments->append(maxTrackBreadth.releaseNonNull());
+        return CSSFunctionValue::create("minmax(", parsedArguments);
+    }
 
-        return createPrimitiveValuePair(minTrackBreadth, maxTrackBreadth);
+    return parseGridBreadth(currentValue);
+}
+
+RefPtr<CSSPrimitiveValue> CSSParser::parseGridBreadth(CSSParserValue& value)
+{
+    if (value.id == CSSValueWebkitMinContent || value.id == CSSValueWebkitMaxContent || value.id == CSSValueAuto)
+        return CSSValuePool::singleton().createIdentifierValue(value.id);
+
+    if (value.unit == CSSPrimitiveValue::CSS_FR) {
+        double flexValue = value.fValue;
+
+        // Fractional unit is a non-negative dimension.
+        if (flexValue <= 0)
+            return nullptr;
+
+        return CSSValuePool::singleton().createValue(flexValue, CSSPrimitiveValue::CSS_FR);
     }
 
-    if (PassRefPtr<CSSPrimitiveValue> trackBreadth = parseGridBreadth(currentValue))
-        return trackBreadth;
+    ValueWithCalculation valueWithCalculation(value);
+    if (!validateUnit(valueWithCalculation, FNonNeg | FLength | FPercent))
+        return nullptr;
 
-    return 0;
+    return createPrimitiveNumericValue(valueWithCalculation);
 }
 
-PassRefPtr<CSSPrimitiveValue> CSSParser::parseGridBreadth(CSSParserValue* currentValue)
+static inline bool isValidGridAutoFlowId(CSSValueID id)
 {
-    if (currentValue->id == CSSValueWebkitMinContent || currentValue->id == CSSValueWebkitMaxContent)
-        return cssValuePool().createIdentifierValue(currentValue->id);
+    return (id == CSSValueRow || id == CSSValueColumn || id == CSSValueDense);
+}
 
-    if (!validUnit(currentValue, FLength | FPercent))
-        return 0;
+RefPtr<CSSValue> CSSParser::parseGridAutoFlow(CSSParserValueList& inputList)
+{
+    // [ row | column ] || dense
+    CSSParserValue* value = inputList.current();
+    if (!value)
+        return nullptr;
+
+    RefPtr<CSSValueList> parsedValues = CSSValueList::createSpaceSeparated();
+
+    // First parameter.
+    CSSValueID firstId = value->id;
+    if (!isValidGridAutoFlowId(firstId))
+        return nullptr;
+
+    // Second parameter, if any.
+    // If second parameter is not valid we should process anyway the first one as we can be inside the "grid" shorthand.
+    value = inputList.next();
+    if (!value || !isValidGridAutoFlowId(value->id)) {
+        if (firstId == CSSValueDense)
+            parsedValues->append(CSSValuePool::singleton().createIdentifierValue(CSSValueRow));
 
-    return createPrimitiveNumericValue(currentValue);
+        parsedValues->append(CSSValuePool::singleton().createIdentifierValue(firstId));
+        return parsedValues;
+    }
+
+    switch (firstId) {
+    case CSSValueRow:
+    case CSSValueColumn:
+        parsedValues->append(CSSValuePool::singleton().createIdentifierValue(firstId));
+        if (value->id == CSSValueDense) {
+            parsedValues->append(CSSValuePool::singleton().createIdentifierValue(value->id));
+            inputList.next();
+        }
+        break;
+    case CSSValueDense:
+        if (value->id == CSSValueRow || value->id == CSSValueColumn) {
+            parsedValues->append(CSSValuePool::singleton().createIdentifierValue(value->id));
+            inputList.next();
+        }
+        parsedValues->append(CSSValuePool::singleton().createIdentifierValue(firstId));
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+        break;
+    }
+
+    return parsedValues;
 }
+#endif /* ENABLE(CSS_GRID_LAYOUT) */
 
 #if ENABLE(DASHBOARD_SUPPORT)
 
@@ -4849,8 +6026,8 @@ static CSSParserValue* skipCommaInDashboardRegion(CSSParserValueList *args)
 {
     if (args->size() == (DASHBOARD_REGION_NUM_PARAMETERS*2-1) ||
          args->size() == (DASHBOARD_REGION_SHORT_NUM_PARAMETERS*2-1)) {
-        CSSParserValue* current = args->current();
-        if (current->unit == CSSParserValue::Operator && current->iValue == ',')
+        CSSParserValue& current = *args->current();
+        if (current.unit == CSSParserValue::Operator && current.iValue == ',')
             return args->next();
     }
     return args->current();
@@ -4865,20 +6042,20 @@ bool CSSParser::parseDashboardRegions(CSSPropertyID propId, bool important)
     if (value->id == CSSValueNone) {
         if (m_valueList->next())
             return false;
-        addProperty(propId, cssValuePool().createIdentifierValue(value->id), important);
+        addProperty(propId, CSSValuePool::singleton().createIdentifierValue(value->id), important);
         return valid;
     }
 
-    RefPtr<DashboardRegion> firstRegion = DashboardRegion::create();
-    DashboardRegion* region = 0;
+    auto firstRegion = DashboardRegion::create();
+    DashboardRegion* region = nullptr;
 
     while (value) {
-        if (region == 0) {
-            region = firstRegion.get();
+        if (!region) {
+            region = firstRegion.ptr();
         } else {
-            RefPtr<DashboardRegion> nextRegion = DashboardRegion::create();
-            region->m_next = nextRegion;
-            region = nextRegion.get();
+            auto nextRegion = DashboardRegion::create();
+            region->m_next = nextRegion.copyRef();
+            region = nextRegion.ptr();
         }
 
         if (value->unit != CSSParserValue::Function) {
@@ -4893,7 +6070,7 @@ bool CSSParser::parseDashboardRegions(CSSPropertyID propId, bool important)
         // dashboard-region(label, type) or dashboard-region(label type)
         // dashboard-region(label, type) or dashboard-region(label type)
         CSSParserValueList* args = value->function->args.get();
-        if (!equalIgnoringCase(value->function->name, "dashboard-region(") || !args) {
+        if (!equalLettersIgnoringASCIICase(value->function->name, "dashboard-region(") || !args) {
             valid = false;
             break;
         }
@@ -4922,9 +6099,9 @@ bool CSSParser::parseDashboardRegions(CSSPropertyID propId, bool important)
             break;
         }
 
-        if (equalIgnoringCase(arg, "circle"))
+        if (equalLettersIgnoringASCIICase(*arg, "circle"))
             region->m_isCircle = true;
-        else if (equalIgnoringCase(arg, "rectangle"))
+        else if (equalLettersIgnoringASCIICase(*arg, "rectangle"))
             region->m_isRectangle = true;
         else {
             valid = false;
@@ -4935,7 +6112,7 @@ bool CSSParser::parseDashboardRegions(CSSPropertyID propId, bool important)
 
         if (numArgs == DASHBOARD_REGION_SHORT_NUM_PARAMETERS || numArgs == (DASHBOARD_REGION_SHORT_NUM_PARAMETERS*2-1)) {
             // This originally used CSSValueInvalid by accident. It might be more logical to use something else.
-            RefPtr<CSSPrimitiveValue> amount = cssValuePool().createIdentifierValue(CSSValueInvalid);
+            RefPtr<CSSPrimitiveValue> amount = CSSValuePool::singleton().createIdentifierValue(CSSValueInvalid);
 
             region->setTop(amount);
             region->setRight(amount);
@@ -4943,18 +6120,16 @@ bool CSSParser::parseDashboardRegions(CSSPropertyID propId, bool important)
             region->setLeft(amount);
         } else {
             // Next four arguments must be offset numbers
-            int i;
-            for (i = 0; i < 4; i++) {
+            for (int i = 0; i < 4; ++i) {
                 arg = args->next();
                 arg = skipCommaInDashboardRegion(args);
 
-                valid = arg->id == CSSValueAuto || validUnit(arg, FLength);
+                ValueWithCalculation argWithCalculation(*arg);
+                valid = arg->id == CSSValueAuto || validateUnit(argWithCalculation, FLength);
                 if (!valid)
                     break;
 
-                RefPtr<CSSPrimitiveValue> amount = arg->id == CSSValueAuto ?
-                    cssValuePool().createIdentifierValue(CSSValueAuto) :
-                    createPrimitiveNumericValue(arg);
+                RefPtr<CSSPrimitiveValue> amount = arg->id == CSSValueAuto ? CSSValuePool::singleton().createIdentifierValue(CSSValueAuto) : createPrimitiveNumericValue(argWithCalculation);
 
                 if (i == 0)
                     region->setTop(amount);
@@ -4974,87 +6149,202 @@ bool CSSParser::parseDashboardRegions(CSSPropertyID propId, bool important)
     }
 
     if (valid)
-        addProperty(propId, cssValuePool().createValue(firstRegion.release()), important);
+        addProperty(propId, CSSValuePool::singleton().createValue(RefPtr<DashboardRegion>(WTFMove(firstRegion))), important);
 
     return valid;
 }
 
 #endif /* ENABLE(DASHBOARD_SUPPORT) */
 
-PassRefPtr<CSSValue> CSSParser::parseCounterContent(CSSParserValueList* args, bool counters)
+#if ENABLE(CSS_GRID_LAYOUT)
+static Vector<String> parseGridTemplateAreasColumnNames(const String& gridRowNames)
+{
+    ASSERT(!gridRowNames.isEmpty());
+    Vector<String> columnNames;
+    // Using StringImpl to avoid checks and indirection in every call to String::operator[].
+    StringImpl& text = *gridRowNames.impl();
+    unsigned length = text.length();
+    unsigned index = 0;
+    while (index < length) {
+        if (text[index] != ' ' && text[index] != '.') {
+            unsigned gridAreaStart = index;
+            while (index < length && text[index] != ' ' && text[index] != '.')
+                index++;
+            columnNames.append(text.substring(gridAreaStart, index - gridAreaStart));
+            continue;
+        }
+
+        if (text[index] == '.') {
+            while (index < length && text[index] == '.')
+                index++;
+            columnNames.append(".");
+            continue;
+        }
+
+        index++;
+    }
+
+    return columnNames;
+}
+
+bool CSSParser::parseGridTemplateAreasRow(NamedGridAreaMap& gridAreaMap, const unsigned rowCount, unsigned& columnCount)
+{
+    CSSParserValue* currentValue = m_valueList->current();
+    if (!currentValue || currentValue->unit != CSSPrimitiveValue::CSS_STRING)
+        return false;
+
+    String gridRowNames = currentValue->string;
+    if (gridRowNames.containsOnlyWhitespace())
+        return false;
+
+    Vector<String> columnNames = parseGridTemplateAreasColumnNames(gridRowNames);
+    if (!columnCount) {
+        columnCount = columnNames.size();
+        ASSERT(columnCount);
+    } else if (columnCount != columnNames.size()) {
+        // The declaration is invalid is all the rows don't have the number of columns.
+        return false;
+    }
+
+    for (unsigned currentColumn = 0; currentColumn < columnCount; ++currentColumn) {
+        const String& gridAreaName = columnNames[currentColumn];
+
+        // Unamed areas are always valid (we consider them to be 1x1).
+        if (gridAreaName == ".")
+            continue;
+
+        // We handle several grid areas with the same name at once to simplify the validation code.
+        unsigned lookAheadColumn;
+        for (lookAheadColumn = currentColumn + 1; lookAheadColumn < columnCount; ++lookAheadColumn) {
+            if (columnNames[lookAheadColumn] != gridAreaName)
+                break;
+        }
+
+        auto gridAreaIterator = gridAreaMap.find(gridAreaName);
+        if (gridAreaIterator == gridAreaMap.end())
+            gridAreaMap.add(gridAreaName, GridCoordinate(GridSpan::definiteGridSpan(rowCount, rowCount + 1), GridSpan::definiteGridSpan(currentColumn, lookAheadColumn)));
+        else {
+            GridCoordinate& gridCoordinate = gridAreaIterator->value;
+
+            // The following checks test that the grid area is a single filled-in rectangle.
+            // 1. The new row is adjacent to the previously parsed row.
+            if (rowCount != gridCoordinate.rows.resolvedFinalPosition().toInt())
+                return false;
+
+            // 2. The new area starts at the same position as the previously parsed area.
+            if (currentColumn != gridCoordinate.columns.resolvedInitialPosition().toInt())
+                return false;
+
+            // 3. The new area ends at the same position as the previously parsed area.
+            if (lookAheadColumn != gridCoordinate.columns.resolvedFinalPosition().toInt())
+                return false;
+
+            gridCoordinate.rows = GridSpan::definiteGridSpan(gridCoordinate.rows.resolvedInitialPosition(), gridCoordinate.rows.resolvedFinalPosition().next());
+        }
+        currentColumn = lookAheadColumn - 1;
+    }
+
+    m_valueList->next();
+    return true;
+}
+
+RefPtr<CSSValue> CSSParser::parseGridTemplateAreas()
+{
+    if (m_valueList->current() && m_valueList->current()->id == CSSValueNone) {
+        m_valueList->next();
+        return CSSValuePool::singleton().createIdentifierValue(CSSValueNone);
+    }
+
+    NamedGridAreaMap gridAreaMap;
+    unsigned rowCount = 0;
+    unsigned columnCount = 0;
+
+    while (m_valueList->current()) {
+        if (!parseGridTemplateAreasRow(gridAreaMap, rowCount, columnCount))
+            return nullptr;
+        ++rowCount;
+    }
+
+    if (!rowCount || !columnCount)
+        return nullptr;
+
+    return CSSGridTemplateAreasValue::create(gridAreaMap, rowCount, columnCount);
+}
+#endif /* ENABLE(CSS_GRID_LAYOUT) */
+
+RefPtr<CSSValue> CSSParser::parseCounterContent(CSSParserValueList& args, bool counters)
 {
-    unsigned numArgs = args->size();
+    unsigned numArgs = args.size();
     if (counters && numArgs != 3 && numArgs != 5)
-        return 0;
+        return nullptr;
     if (!counters && numArgs != 1 && numArgs != 3)
-        return 0;
+        return nullptr;
 
-    CSSParserValue* i = args->current();
-    if (i->unit != CSSPrimitiveValue::CSS_IDENT)
-        return 0;
-    RefPtr<CSSPrimitiveValue> identifier = createPrimitiveStringValue(i);
+    CSSParserValue* argument = args.current();
+    if (argument->unit != CSSPrimitiveValue::CSS_IDENT)
+        return nullptr;
+    RefPtr<CSSPrimitiveValue> identifier = createPrimitiveStringValue(*argument);
 
     RefPtr<CSSPrimitiveValue> separator;
     if (!counters)
-        separator = cssValuePool().createValue(String(), CSSPrimitiveValue::CSS_STRING);
+        separator = CSSValuePool::singleton().createValue(String(), CSSPrimitiveValue::CSS_STRING);
     else {
-        i = args->next();
-        if (i->unit != CSSParserValue::Operator || i->iValue != ',')
-            return 0;
+        argument = args.next();
+        if (argument->unit != CSSParserValue::Operator || argument->iValue != ',')
+            return nullptr;
 
-        i = args->next();
-        if (i->unit != CSSPrimitiveValue::CSS_STRING)
-            return 0;
+        argument = args.next();
+        if (argument->unit != CSSPrimitiveValue::CSS_STRING)
+            return nullptr;
 
-        separator = createPrimitiveStringValue(i);
+        separator = createPrimitiveStringValue(*argument);
     }
 
     RefPtr<CSSPrimitiveValue> listStyle;
-    i = args->next();
-    if (!i) // Make the list style default decimal
-        listStyle = cssValuePool().createIdentifierValue(CSSValueDecimal);
+    argument = args.next();
+    if (!argument) // Make the list style default decimal
+        listStyle = CSSValuePool::singleton().createIdentifierValue(CSSValueDecimal);
     else {
-        if (i->unit != CSSParserValue::Operator || i->iValue != ',')
-            return 0;
+        if (argument->unit != CSSParserValue::Operator || argument->iValue != ',')
+            return nullptr;
 
-        i = args->next();
-        if (i->unit != CSSPrimitiveValue::CSS_IDENT)
-            return 0;
+        argument = args.next();
+        if (argument->unit != CSSPrimitiveValue::CSS_IDENT)
+            return nullptr;
 
         CSSValueID listStyleID = CSSValueInvalid;
-        if (i->id == CSSValueNone || (i->id >= CSSValueDisc && i->id <= CSSValueKatakanaIroha))
-            listStyleID = i->id;
+        if (argument->id == CSSValueNone || (argument->id >= CSSValueDisc && argument->id <= CSSValueKatakanaIroha))
+            listStyleID = argument->id;
         else
-            return 0;
+            return nullptr;
 
-        listStyle = cssValuePool().createIdentifierValue(listStyleID);
+        listStyle = CSSValuePool::singleton().createIdentifierValue(listStyleID);
     }
 
-    return cssValuePool().createValue(Counter::create(identifier.release(), listStyle.release(), separator.release()));
+    return CSSValuePool::singleton().createValue(Counter::create(identifier.release(), listStyle.release(), separator.release()));
 }
 
 bool CSSParser::parseClipShape(CSSPropertyID propId, bool important)
 {
-    CSSParserValue* value = m_valueList->current();
-    CSSParserValueList* args = value->function->args.get();
+    CSSParserValue& value = *m_valueList->current();
+    CSSParserValueList* args = value.function->args.get();
 
-    if (!equalIgnoringCase(value->function->name, "rect(") || !args)
+    if (!equalLettersIgnoringASCIICase(value.function->name, "rect(") || !args)
         return false;
 
     // rect(t, r, b, l) || rect(t r b l)
     if (args->size() != 4 && args->size() != 7)
         return false;
-    RefPtr<Rect> rect = Rect::create();
+    auto rect = Rect::create();
     bool valid = true;
     int i = 0;
-    CSSParserValue* a = args->current();
-    while (a) {
-        valid = a->id == CSSValueAuto || validUnit(a, FLength);
+    CSSParserValue* argument = args->current();
+    while (argument) {
+        ValueWithCalculation argumentWithCalculation(*argument);
+        valid = argument->id == CSSValueAuto || validateUnit(argumentWithCalculation, FLength);
         if (!valid)
             break;
-        RefPtr<CSSPrimitiveValue> length = a->id == CSSValueAuto ?
-            cssValuePool().createIdentifierValue(CSSValueAuto) :
-            createPrimitiveNumericValue(a);
+        RefPtr<CSSPrimitiveValue> length = argument->id == CSSValueAuto ? CSSValuePool::singleton().createIdentifierValue(CSSValueAuto) : createPrimitiveNumericValue(argumentWithCalculation);
         if (i == 0)
             rect->setTop(length);
         else if (i == 1)
@@ -5063,10 +6353,10 @@ bool CSSParser::parseClipShape(CSSPropertyID propId, bool important)
             rect->setBottom(length);
         else
             rect->setLeft(length);
-        a = args->next();
-        if (a && args->size() == 7) {
-            if (a->unit == CSSParserValue::Operator && a->iValue == ',') {
-                a = args->next();
+        argument = args->next();
+        if (argument && args->size() == 7) {
+            if (argument->unit == CSSParserValue::Operator && argument->iValue == ',') {
+                argument = args->next();
             } else {
                 valid = false;
                 break;
@@ -5075,304 +6365,440 @@ bool CSSParser::parseClipShape(CSSPropertyID propId, bool important)
         i++;
     }
     if (valid) {
-        addProperty(propId, cssValuePool().createValue(rect.release()), important);
+        addProperty(propId, CSSValuePool::singleton().createValue(WTFMove(rect)), important);
         m_valueList->next();
         return true;
     }
     return false;
 }
 
-PassRefPtr<CSSBasicShape> CSSParser::parseBasicShapeRectangle(CSSParserValueList* args)
+static void completeBorderRadii(RefPtr<CSSPrimitiveValue> radii[4])
 {
-    ASSERT(args);
+    if (radii[3])
+        return;
+    if (!radii[2]) {
+        if (!radii[1])
+            radii[1] = radii[0];
+        radii[2] = radii[0];
+    }
+    radii[3] = radii[1];
+}
 
-    // rect(x, y, width, height, [[rx], ry])
-    if (args->size() != 7 && args->size() != 9 && args->size() != 11)
-        return 0;
+// FIXME: This should be refactored with CSSParser::parseBorderRadius.
+// CSSParser::parseBorderRadius contains support for some legacy radius construction.
+RefPtr<CSSBasicShape> CSSParser::parseInsetRoundedCorners(PassRefPtr<CSSBasicShapeInset> shape, CSSParserValueList& args)
+{
+    CSSParserValue* argument = args.next();
 
-    RefPtr<CSSBasicShapeRectangle> shape = CSSBasicShapeRectangle::create();
+    if (!argument)
+        return nullptr;
 
-    unsigned argumentNumber = 0;
-    CSSParserValue* argument = args->current();
+    Vector<CSSParserValue*> radiusArguments;
     while (argument) {
-        Units unitFlags = FLength | FPercent;
-        if (argumentNumber > 1) {
-            // Arguments width, height, rx, and ry cannot be negative.
-            unitFlags = unitFlags | FNonNeg;
-        }
-        if (!validUnit(argument, unitFlags))
-            return 0;
-
-        RefPtr<CSSPrimitiveValue> length = createPrimitiveNumericValue(argument);
-        ASSERT(argumentNumber < 6);
-        switch (argumentNumber) {
-        case 0:
-            shape->setX(length);
-            break;
-        case 1:
-            shape->setY(length);
-            break;
-        case 2:
-            shape->setWidth(length);
-            break;
-        case 3:
-            shape->setHeight(length);
-            break;
-        case 4:
-            shape->setRadiusX(length);
-            break;
-        case 5:
-            shape->setRadiusY(length);
-            break;
-        }
-        argument = args->next();
-        if (argument) {
-            if (!isComma(argument))
-                return 0;
+        radiusArguments.append(argument);
+        argument = args.next();
+    }
 
-            argument = args->next();
+    unsigned num = radiusArguments.size();
+    if (!num || num > 9)
+        return nullptr;
+
+    RefPtr<CSSPrimitiveValue> radii[2][4];
+
+    unsigned indexAfterSlash = 0;
+    for (unsigned i = 0; i < num; ++i) {
+        CSSParserValue& value = *radiusArguments.at(i);
+        if (value.unit == CSSParserValue::Operator) {
+            if (value.iValue != '/')
+                return nullptr;
+
+            if (!i || indexAfterSlash || i + 1 == num || num > i + 5)
+                return nullptr;
+
+            indexAfterSlash = i + 1;
+            completeBorderRadii(radii[0]);
+            continue;
         }
-        argumentNumber++;
+
+        if (i - indexAfterSlash >= 4)
+            return nullptr;
+
+        ValueWithCalculation valueWithCalculation(value);
+        if (!validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg))
+            return nullptr;
+
+        RefPtr<CSSPrimitiveValue> radius = createPrimitiveNumericValue(valueWithCalculation);
+
+        if (!indexAfterSlash)
+            radii[0][i] = radius;
+        else
+            radii[1][i - indexAfterSlash] = radius.release();
     }
 
-    if (argumentNumber < 4)
-        return 0;
+    if (!indexAfterSlash) {
+        completeBorderRadii(radii[0]);
+        for (unsigned i = 0; i < 4; ++i)
+            radii[1][i] = radii[0][i];
+    } else
+        completeBorderRadii(radii[1]);
+
+    shape->setTopLeftRadius(createPrimitiveValuePair(radii[0][0].release(), radii[1][0].release()));
+    shape->setTopRightRadius(createPrimitiveValuePair(radii[0][1].release(), radii[1][1].release()));
+    shape->setBottomRightRadius(createPrimitiveValuePair(radii[0][2].release(), radii[1][2].release()));
+    shape->setBottomLeftRadius(createPrimitiveValuePair(radii[0][3].release(), radii[1][3].release()));
+
     return shape;
 }
 
-PassRefPtr<CSSBasicShape> CSSParser::parseBasicShapeInsetRectangle(CSSParserValueList* args)
+RefPtr<CSSBasicShape> CSSParser::parseBasicShapeInset(CSSParserValueList& args)
 {
-    ASSERT(args);
+    RefPtr<CSSBasicShapeInset> shape = CSSBasicShapeInset::create();
 
-    // inset-rectangle(top, right, bottom, left, [[rx], ry])
-    if (args->size() != 7 && args->size() != 9 && args->size() != 11)
-        return 0;
-
-    RefPtr<CSSBasicShapeInsetRectangle> shape = CSSBasicShapeInsetRectangle::create();
-
-    unsigned argumentNumber = 0;
-    CSSParserValue* argument = args->current();
+    CSSParserValue* argument = args.current();
+    Vector<RefPtr<CSSPrimitiveValue> > widthArguments;
+    bool hasRoundedInset = false;
     while (argument) {
-        Units unitFlags = FLength | FPercent | FNonNeg;
-        if (!validUnit(argument, unitFlags))
-            return 0;
-
-        RefPtr<CSSPrimitiveValue> length = createPrimitiveNumericValue(argument);
-        ASSERT(argumentNumber < 6);
-        switch (argumentNumber) {
-        case 0:
-            shape->setTop(length);
-            break;
-        case 1:
-            shape->setRight(length);
-            break;
-        case 2:
-            shape->setBottom(length);
-            break;
-        case 3:
-            shape->setLeft(length);
-            break;
-        case 4:
-            shape->setRadiusX(length);
-            break;
-        case 5:
-            shape->setRadiusY(length);
+        if (argument->unit == CSSPrimitiveValue::CSS_IDENT && equalLettersIgnoringASCIICase(argument->string, "round")) {
+            hasRoundedInset = true;
             break;
         }
-        argument = args->next();
-        if (argument) {
-            if (!isComma(argument))
-                return 0;
 
-            argument = args->next();
+        Units unitFlags = FLength | FPercent;
+        ValueWithCalculation argumentWithCalculation(*argument);
+        if (!validateUnit(argumentWithCalculation, unitFlags) || widthArguments.size() > 4)
+            return nullptr;
+
+        widthArguments.append(createPrimitiveNumericValue(argumentWithCalculation));
+        argument = args.next();
+    }
+
+    switch (widthArguments.size()) {
+    case 1: {
+        shape->updateShapeSize1Value(widthArguments[0].get());
+        break;
+    }
+    case 2: {
+        shape->updateShapeSize2Values(widthArguments[0].get(), widthArguments[1].get());
+        break;
         }
-        argumentNumber++;
+    case 3: {
+        shape->updateShapeSize3Values(widthArguments[0].get(), widthArguments[1].get(), widthArguments[2].get());
+        break;
+    }
+    case 4: {
+        shape->updateShapeSize4Values(widthArguments[0].get(), widthArguments[1].get(), widthArguments[2].get(), widthArguments[3].get());
+        break;
+    }
+    default:
+        return nullptr;
     }
 
-    if (argumentNumber < 4)
-        return 0;
+    if (hasRoundedInset)
+        return parseInsetRoundedCorners(shape, args);
     return shape;
 }
 
-PassRefPtr<CSSBasicShape> CSSParser::parseBasicShapeCircle(CSSParserValueList* args)
+RefPtr<CSSPrimitiveValue> CSSParser::parseShapeRadius(CSSParserValue& value)
 {
-    ASSERT(args);
+    if (value.id == CSSValueClosestSide || value.id == CSSValueFarthestSide)
+        return CSSValuePool::singleton().createIdentifierValue(value.id);
 
-    // circle(centerX, centerY, radius)
-    if (args->size() != 5)
-        return 0;
+    ValueWithCalculation valueWithCalculation(value);
+    if (!validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg))
+        return nullptr;
+
+    return createPrimitiveNumericValue(valueWithCalculation);
+}
 
+RefPtr<CSSBasicShape> CSSParser::parseBasicShapeCircle(CSSParserValueList& args)
+{
+    // circle(radius)
+    // circle(radius at <position>)
+    // circle(at <position>)
+    // where position defines centerX and centerY using a CSS <position> data type.
     RefPtr<CSSBasicShapeCircle> shape = CSSBasicShapeCircle::create();
 
-    unsigned argumentNumber = 0;
-    CSSParserValue* argument = args->current();
-    while (argument) {
-        Units unitFlags = FLength | FPercent;
-        if (argumentNumber == 2) {
-            // Argument radius cannot be negative.
-            unitFlags = unitFlags | FNonNeg;
-        }
+    for (CSSParserValue* argument = args.current(); argument; argument = args.next()) {
+        // The call to parseFillPosition below should consume all of the
+        // arguments except the first two. Thus, and index greater than one
+        // indicates an invalid production.
+        if (args.currentIndex() > 1)
+            return nullptr;
 
-        if (!validUnit(argument, unitFlags))
-            return 0;
+        if (!args.currentIndex() && argument->id != CSSValueAt) {
+            if (RefPtr<CSSPrimitiveValue> radius = parseShapeRadius(*argument)) {
+                shape->setRadius(radius);
+                continue;
+            }
 
-        RefPtr<CSSPrimitiveValue> length = createPrimitiveNumericValue(argument);
-        ASSERT(argumentNumber < 3);
-        switch (argumentNumber) {
-        case 0:
-            shape->setCenterX(length);
-            break;
-        case 1:
-            shape->setCenterY(length);
-            break;
-        case 2:
-            shape->setRadius(length);
-            break;
+            return nullptr;
         }
 
-        argument = args->next();
-        if (argument) {
-            if (!isComma(argument))
-                return 0;
-            argument = args->next();
-        }
-        argumentNumber++;
+        if (argument->id == CSSValueAt && args.next()) {
+            RefPtr<CSSPrimitiveValue> centerX;
+            RefPtr<CSSPrimitiveValue> centerY;
+            parseFillPosition(args, centerX, centerY);
+            if (centerX && centerY && !args.current()) {
+                shape->setCenterX(centerX);
+                shape->setCenterY(centerY);
+            } else
+                return nullptr;
+        } else
+            return nullptr;
     }
 
-    if (argumentNumber < 3)
-        return 0;
     return shape;
 }
 
-PassRefPtr<CSSBasicShape> CSSParser::parseBasicShapeEllipse(CSSParserValueList* args)
+RefPtr<CSSBasicShape> CSSParser::parseBasicShapeEllipse(CSSParserValueList& args)
 {
-    ASSERT(args);
+    // ellipse(radiusX)
+    // ellipse(radiusX at <position>)
+    // ellipse(radiusX radiusY)
+    // ellipse(radiusX radiusY at <position>)
+    // ellipse(at <position>)
+    // where position defines centerX and centerY using a CSS <position> data type.
+    RefPtr<CSSBasicShapeEllipse> shape = CSSBasicShapeEllipse::create();
 
-    // ellipse(centerX, centerY, radiusX, radiusY)
-    if (args->size() != 7)
-        return 0;
+    for (CSSParserValue* argument = args.current(); argument; argument = args.next()) {
+        // The call to parseFillPosition below should consume all of the
+        // arguments except the first three. Thus, an index greater than two
+        // indicates an invalid production.
+        if (args.currentIndex() > 2)
+            return nullptr;
+
+        if (args.currentIndex() < 2 && argument->id != CSSValueAt) {
+            if (RefPtr<CSSPrimitiveValue> radius = parseShapeRadius(*argument)) {
+                if (!shape->radiusX())
+                    shape->setRadiusX(radius);
+                else
+                    shape->setRadiusY(radius);
+                continue;
+            }
 
-    RefPtr<CSSBasicShapeEllipse> shape = CSSBasicShapeEllipse::create();
-    unsigned argumentNumber = 0;
-    CSSParserValue* argument = args->current();
-    while (argument) {
-        Units unitFlags = FLength | FPercent;
-        if (argumentNumber > 1) {
-            // Arguments radiusX and radiusY cannot be negative.
-            unitFlags = unitFlags | FNonNeg;
-        }
-        if (!validUnit(argument, unitFlags))
-            return 0;
-
-        RefPtr<CSSPrimitiveValue> length = createPrimitiveNumericValue(argument);
-        ASSERT(argumentNumber < 4);
-        switch (argumentNumber) {
-        case 0:
-            shape->setCenterX(length);
-            break;
-        case 1:
-            shape->setCenterY(length);
-            break;
-        case 2:
-            shape->setRadiusX(length);
-            break;
-        case 3:
-            shape->setRadiusY(length);
-            break;
+            return nullptr;
         }
 
-        argument = args->next();
-        if (argument) {
-            if (!isComma(argument))
-                return 0;
-            argument = args->next();
-        }
-        argumentNumber++;
+        if (argument->id != CSSValueAt || !args.next()) // expecting ellipse(.. at <position>)
+            return nullptr;
+
+        RefPtr<CSSPrimitiveValue> centerX;
+        RefPtr<CSSPrimitiveValue> centerY;
+        parseFillPosition(args, centerX, centerY);
+        if (!centerX || !centerY || args.current())
+            return nullptr;
+
+        shape->setCenterX(centerX);
+        shape->setCenterY(centerY);
     }
 
-    if (argumentNumber < 4)
-        return 0;
     return shape;
 }
 
-PassRefPtr<CSSBasicShape> CSSParser::parseBasicShapePolygon(CSSParserValueList* args)
+RefPtr<CSSBasicShape> CSSParser::parseBasicShapePolygon(CSSParserValueList& args)
 {
-    ASSERT(args);
-
-    unsigned size = args->size();
+    unsigned size = args.size();
     if (!size)
-        return 0;
+        return nullptr;
 
     RefPtr<CSSBasicShapePolygon> shape = CSSBasicShapePolygon::create();
 
-    CSSParserValue* argument = args->current();
+    CSSParserValue* argument = args.current();
     if (argument->id == CSSValueEvenodd || argument->id == CSSValueNonzero) {
         shape->setWindRule(argument->id == CSSValueEvenodd ? RULE_EVENODD : RULE_NONZERO);
 
-        if (!isComma(args->next()))
-            return 0;
+        if (!isComma(args.next()))
+            return nullptr;
 
-        argument = args->next();
+        argument = args.next();
         size -= 2;
     }
 
     // <length> <length>, ... <length> <length> -> each pair has 3 elements except the last one
     if (!size || (size % 3) - 2)
-        return 0;
+        return nullptr;
 
     CSSParserValue* argumentX = argument;
     while (argumentX) {
-        if (!validUnit(argumentX, FLength | FPercent))
-            return 0;
 
-        CSSParserValue* argumentY = args->next();
-        if (!argumentY || !validUnit(argumentY, FLength | FPercent))
-            return 0;
+        ValueWithCalculation argumentXWithCalculation(*argumentX);
+        if (!validateUnit(argumentXWithCalculation, FLength | FPercent))
+            return nullptr;
+        RefPtr<CSSPrimitiveValue> xLength = createPrimitiveNumericValue(argumentXWithCalculation);
 
-        RefPtr<CSSPrimitiveValue> xLength = createPrimitiveNumericValue(argumentX);
-        RefPtr<CSSPrimitiveValue> yLength = createPrimitiveNumericValue(argumentY);
+        CSSParserValue* argumentY = args.next();
+        if (!argumentY)
+            return nullptr;
+        ValueWithCalculation argumentYWithCalculation(*argumentY);
+        if (!validateUnit(argumentYWithCalculation, FLength | FPercent))
+            return nullptr;
+        RefPtr<CSSPrimitiveValue> yLength = createPrimitiveNumericValue(argumentYWithCalculation);
 
         shape->appendPoint(xLength.release(), yLength.release());
 
-        CSSParserValue* commaOrNull = args->next();
+        CSSParserValue* commaOrNull = args.next();
         if (!commaOrNull)
-            argumentX = 0;
+            argumentX = nullptr;
         else if (!isComma(commaOrNull)) 
-            return 0;
+            return nullptr;
         else 
-            argumentX = args->next();
+            argumentX = args.next();
     }
 
     return shape;
 }
 
-bool CSSParser::parseBasicShape(CSSPropertyID propId, bool important)
+RefPtr<CSSBasicShape> CSSParser::parseBasicShapePath(CSSParserValueList& args)
+{
+    unsigned size = args.size();
+    if (size != 1 && size != 3)
+        return nullptr;
+
+    WindRule windRule = RULE_NONZERO;
+
+    CSSParserValue* argument = args.current();
+    if (argument->id == CSSValueEvenodd || argument->id == CSSValueNonzero) {
+        windRule = argument->id == CSSValueEvenodd ? RULE_EVENODD : RULE_NONZERO;
+
+        if (!isComma(args.next()))
+            return nullptr;
+        argument = args.next();
+    }
+
+    if (argument->unit != CSSPrimitiveValue::CSS_STRING)
+        return nullptr;
+
+    auto byteStream = std::make_unique<SVGPathByteStream>();
+    if (!buildSVGPathByteStreamFromString(argument->string, *byteStream, UnalteredParsing))
+        return nullptr;
+
+    RefPtr<CSSBasicShapePath> shape = CSSBasicShapePath::create(WTFMove(byteStream));
+    shape->setWindRule(windRule);
+
+    args.next();
+    return shape;
+}
+
+static bool isBoxValue(CSSValueID valueId, CSSPropertyID propId)
+{
+    switch (valueId) {
+    case CSSValueContentBox:
+    case CSSValuePaddingBox:
+    case CSSValueBorderBox:
+    case CSSValueMarginBox:
+        return true;
+    case CSSValueFill:
+    case CSSValueStroke:
+    case CSSValueViewBox:
+        return propId == CSSPropertyWebkitClipPath;
+    default: break;
+    }
+
+    return false;
+}
+
+RefPtr<CSSValue> CSSParser::parseBasicShapeAndOrBox(CSSPropertyID propId)
 {
     CSSParserValue* value = m_valueList->current();
-    ASSERT(value->unit == CSSParserValue::Function);
-    CSSParserValueList* args = value->function->args.get();
+
+    bool shapeFound = false;
+    bool boxFound = false;
+    CSSValueID valueId;
+
+    RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+    for (unsigned i = 0; i < 2; ++i) {
+        if (!value)
+            break;
+        valueId = value->id;
+        if (value->unit == CSSParserValue::Function && !shapeFound) {
+            // parseBasicShape already asks for the next value list item.
+            RefPtr<CSSPrimitiveValue> shapeValue = parseBasicShape();
+            if (!shapeValue)
+                return nullptr;
+            list->append(shapeValue.releaseNonNull());
+            shapeFound = true;
+        } else if (isBoxValue(valueId, propId) && !boxFound) {
+            RefPtr<CSSPrimitiveValue> parsedValue = CSSValuePool::singleton().createIdentifierValue(valueId);
+            list->append(parsedValue.releaseNonNull());
+            boxFound = true;
+            m_valueList->next();
+        } else
+            return nullptr;
+        value = m_valueList->current();
+    }
+
+    if (m_valueList->current())
+        return nullptr;
+    return list;
+}
+
+#if ENABLE(CSS_SHAPES)
+RefPtr<CSSValue> CSSParser::parseShapeProperty(CSSPropertyID propId)
+{
+    if (!RuntimeEnabledFeatures::sharedFeatures().cssShapesEnabled())
+        return nullptr;
+
+    CSSParserValue& value = *m_valueList->current();
+    CSSValueID valueId = value.id;
+
+    if (valueId == CSSValueNone) {
+        m_valueList->next();
+        return CSSValuePool::singleton().createIdentifierValue(valueId);
+    }
+
+    RefPtr<CSSValue> imageValue;
+    if (valueId != CSSValueNone && parseFillImage(*m_valueList, imageValue)) {
+        m_valueList->next();
+        return imageValue;
+    }
+
+    return parseBasicShapeAndOrBox(propId);
+}
+#endif
+
+RefPtr<CSSValue> CSSParser::parseClipPath()
+{
+    CSSParserValue& value = *m_valueList->current();
+    CSSValueID valueId = value.id;
+
+    if (valueId == CSSValueNone) {
+        m_valueList->next();
+        return CSSValuePool::singleton().createIdentifierValue(valueId);
+    }
+    if (value.unit == CSSPrimitiveValue::CSS_URI) {
+        m_valueList->next();
+        return CSSPrimitiveValue::create(value.string, CSSPrimitiveValue::CSS_URI);
+    }
+
+    return parseBasicShapeAndOrBox(CSSPropertyWebkitClipPath);
+}
+
+RefPtr<CSSPrimitiveValue> CSSParser::parseBasicShape()
+{
+    CSSParserValue& value = *m_valueList->current();
+    ASSERT(value.unit == CSSParserValue::Function);
+    CSSParserValueList* args = value.function->args.get();
 
     if (!args)
-        return false;
+        return nullptr;
 
     RefPtr<CSSBasicShape> shape;
-    if (equalIgnoringCase(value->function->name, "rectangle("))
-        shape = parseBasicShapeRectangle(args);
-    else if (equalIgnoringCase(value->function->name, "circle("))
-        shape = parseBasicShapeCircle(args);
-    else if (equalIgnoringCase(value->function->name, "ellipse("))
-        shape = parseBasicShapeEllipse(args);
-    else if (equalIgnoringCase(value->function->name, "polygon("))
-        shape = parseBasicShapePolygon(args);
-    else if (equalIgnoringCase(value->function->name, "inset-rectangle("))
-        shape = parseBasicShapeInsetRectangle(args);
+    if (equalLettersIgnoringASCIICase(value.function->name, "circle("))
+        shape = parseBasicShapeCircle(*args);
+    else if (equalLettersIgnoringASCIICase(value.function->name, "ellipse("))
+        shape = parseBasicShapeEllipse(*args);
+    else if (equalLettersIgnoringASCIICase(value.function->name, "polygon("))
+        shape = parseBasicShapePolygon(*args);
+    else if (equalLettersIgnoringASCIICase(value.function->name, "path("))
+        shape = parseBasicShapePath(*args);
+    else if (equalLettersIgnoringASCIICase(value.function->name, "inset("))
+        shape = parseBasicShapeInset(*args);
 
     if (!shape)
-        return false;
+        return nullptr;
 
-    addProperty(propId, cssValuePool().createValue(shape.release()), important);
     m_valueList->next();
-    return true;
+    return CSSValuePool::singleton().createValue(shape.releaseNonNull());
 }
 
 // [ 'font-style' || 'font-variant' || 'font-weight' ]? 'font-size' [ / 'line-height' ]? 'font-family'
@@ -5391,12 +6817,12 @@ bool CSSParser::parseFont(bool important)
     bool fontWeightParsed = false;
     CSSParserValue* value;
     while ((value = m_valueList->current())) {
-        if (!fontStyleParsed && isValidKeywordPropertyAndValue(CSSPropertyFontStyle, value->id, m_context)) {
-            addProperty(CSSPropertyFontStyle, cssValuePool().createIdentifierValue(value->id), important);
+        if (!fontStyleParsed && isValidKeywordPropertyAndValue(CSSPropertyFontStyle, value->id, m_context, m_styleSheet)) {
+            addProperty(CSSPropertyFontStyle, CSSValuePool::singleton().createIdentifierValue(value->id), important);
             fontStyleParsed = true;
         } else if (!fontVariantParsed && (value->id == CSSValueNormal || value->id == CSSValueSmallCaps)) {
             // Font variant in the shorthand is particular, it only accepts normal or small-caps.
-            addProperty(CSSPropertyFontVariant, cssValuePool().createIdentifierValue(value->id), important);
+            addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(value->id), important);
             fontVariantParsed = true;
         } else if (!fontWeightParsed && parseFontWeight(important))
             fontWeightParsed = true;
@@ -5409,11 +6835,11 @@ bool CSSParser::parseFont(bool important)
         return false;
 
     if (!fontStyleParsed)
-        addProperty(CSSPropertyFontStyle, cssValuePool().createIdentifierValue(CSSValueNormal), important, true);
+        addProperty(CSSPropertyFontStyle, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
     if (!fontVariantParsed)
-        addProperty(CSSPropertyFontVariant, cssValuePool().createIdentifierValue(CSSValueNormal), important, true);
+        addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
     if (!fontWeightParsed)
-        addProperty(CSSPropertyFontWeight, cssValuePool().createIdentifierValue(CSSValueNormal), important, true);
+        addProperty(CSSPropertyFontWeight, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
 
     // Now a font size _must_ come.
     // <absolute-size> | <relative-size> | <length> | <percentage> | inherit
@@ -5424,7 +6850,7 @@ bool CSSParser::parseFont(bool important)
     if (!value)
         return false;
 
-    if (isForwardSlashOperator(value)) {
+    if (isForwardSlashOperator(*value)) {
         // The line-height property.
         value = m_valueList->next();
         if (!value)
@@ -5432,7 +6858,7 @@ bool CSSParser::parseFont(bool important)
         if (!parseLineHeight(important))
             return false;
     } else
-        addProperty(CSSPropertyLineHeight, cssValuePool().createIdentifierValue(CSSValueNormal), important, true);
+        addProperty(CSSPropertyLineHeight, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important, true);
 
     // Font family must come now.
     RefPtr<CSSValue> parsedFamilyValue = parseFontFamily();
@@ -5450,9 +6876,33 @@ bool CSSParser::parseFont(bool important)
     return true;
 }
 
+void CSSParser::parseSystemFont(bool important)
+{
+    ASSERT(m_valueList->size() == 1);
+    CSSValueID systemFontID = m_valueList->valueAt(0)->id;
+    ASSERT(systemFontID >= CSSValueCaption && systemFontID <= CSSValueStatusBar);
+    m_valueList->next();
+
+    FontCascadeDescription fontDescription;
+    RenderTheme::defaultTheme()->systemFont(systemFontID, fontDescription);
+    if (!fontDescription.isAbsoluteSize())
+        return;
+
+    // We must set font's constituent properties, even for system fonts, so the cascade functions correctly.
+    ShorthandScope scope(this, CSSPropertyFont);
+    addProperty(CSSPropertyFontStyle, CSSValuePool::singleton().createIdentifierValue(fontDescription.italic() == FontItalicOn ? CSSValueItalic : CSSValueNormal), important);
+    addProperty(CSSPropertyFontWeight, CSSValuePool::singleton().createValue(fontDescription.weight()), important);
+    addProperty(CSSPropertyFontSize, CSSValuePool::singleton().createValue(fontDescription.specifiedSize(), CSSPrimitiveValue::CSS_PX), important);
+    Ref<CSSValueList> fontFamilyList = CSSValueList::createCommaSeparated();
+    fontFamilyList->append(CSSValuePool::singleton().createFontFamilyValue(fontDescription.familyAt(0), FromSystemFontID::Yes));
+    addProperty(CSSPropertyFontFamily, WTFMove(fontFamilyList), important);
+    addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important);
+    addProperty(CSSPropertyLineHeight, CSSValuePool::singleton().createIdentifierValue(CSSValueNormal), important);
+}
+
 class FontFamilyValueBuilder {
 public:
-    FontFamilyValueBuilder(CSSValueList* list)
+    FontFamilyValueBuilder(CSSValueList& list)
         : m_list(list)
     {
     }
@@ -5474,21 +6924,27 @@ public:
     {
         if (m_builder.isEmpty())
             return;
-        m_list->append(cssValuePool().createFontFamilyValue(m_builder.toString()));
+        m_list.append(CSSValuePool::singleton().createFontFamilyValue(m_builder.toString()));
         m_builder.clear();
     }
 
 private:
     StringBuilder m_builder;
-    CSSValueList* m_list;
+    CSSValueList& m_list;
 };
 
-PassRefPtr<CSSValueList> CSSParser::parseFontFamily()
+static bool valueIsCSSKeyword(const CSSParserValue& value)
+{
+    // FIXME: when we add "unset", we should handle it here.
+    return value.id == CSSValueInitial || value.id == CSSValueInherit || value.id == CSSValueDefault;
+}
+
+RefPtr<CSSValueList> CSSParser::parseFontFamily()
 {
     RefPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     CSSParserValue* value = m_valueList->current();
 
-    FontFamilyValueBuilder familyBuilder(list.get());
+    FontFamilyValueBuilder familyBuilder(*list);
     bool inFamily = false;
 
     while (value) {
@@ -5499,7 +6955,7 @@ PassRefPtr<CSSValueList> CSSParser::parseFontFamily()
             ((nextValue->id >= CSSValueSerif && nextValue->id <= CSSValueWebkitBody) ||
             (nextValue->unit == CSSPrimitiveValue::CSS_STRING || nextValue->unit == CSSPrimitiveValue::CSS_IDENT));
 
-        bool valueIsKeyword = value->id == CSSValueInitial || value->id == CSSValueInherit || value->id == CSSValueDefault;
+        bool valueIsKeyword = valueIsCSSKeyword(*value);
         if (valueIsKeyword && !inFamily) {
             if (nextValBreaksFont)
                 value = m_valueList->next();
@@ -5512,7 +6968,7 @@ PassRefPtr<CSSValueList> CSSParser::parseFontFamily()
             if (inFamily)
                 familyBuilder.add(value->string);
             else if (nextValBreaksFont || !nextValIsFontName)
-                list->append(cssValuePool().createIdentifierValue(value->id));
+                list->append(CSSValuePool::singleton().createIdentifierValue(value->id));
             else {
                 familyBuilder.commit();
                 familyBuilder.add(value->string);
@@ -5522,12 +6978,12 @@ PassRefPtr<CSSValueList> CSSParser::parseFontFamily()
             // Strings never share in a family name.
             inFamily = false;
             familyBuilder.commit();
-            list->append(cssValuePool().createFontFamilyValue(value->string));
+            list->append(CSSValuePool::singleton().createFontFamilyValue(value->string));
         } else if (value->unit == CSSPrimitiveValue::CSS_IDENT) {
             if (inFamily)
                 familyBuilder.add(value->string);
             else if (nextValBreaksFont || !nextValIsFontName)
-                list->append(cssValuePool().createFontFamilyValue(value->string));
+                list->append(CSSValuePool::singleton().createFontFamilyValue(value->string));
             else {
                 familyBuilder.commit();
                 familyBuilder.add(value->string);
@@ -5553,87 +7009,40 @@ PassRefPtr<CSSValueList> CSSParser::parseFontFamily()
     familyBuilder.commit();
 
     if (!list->length())
-        list = 0;
-    return list.release();
+        list = nullptr;
+    return list;
 }
 
 bool CSSParser::parseLineHeight(bool important)
 {
-    CSSParserValue* value = m_valueList->current();
-    CSSValueID id = value->id;
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    CSSValueID id = valueWithCalculation.value().id;
     bool validPrimitive = false;
     // normal | <number> | <length> | <percentage> | inherit
     if (id == CSSValueNormal)
         validPrimitive = true;
     else
-        validPrimitive = (!id && validUnit(value, FNumber | FLength | FPercent | FNonNeg));
+        validPrimitive = (!id && validateUnit(valueWithCalculation, FNumber | FLength | FPercent | FNonNeg));
     if (validPrimitive && (!m_valueList->next() || inShorthand()))
-        addProperty(CSSPropertyLineHeight, parseValidPrimitive(id, value), important);
+        addProperty(CSSPropertyLineHeight, parseValidPrimitive(id, valueWithCalculation), important);
     return validPrimitive;
 }
 
 bool CSSParser::parseFontSize(bool important)
 {
-    CSSParserValue* value = m_valueList->current();
-    CSSValueID id = value->id;
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+    CSSValueID id = valueWithCalculation.value().id;
     bool validPrimitive = false;
     // <absolute-size> | <relative-size> | <length> | <percentage> | inherit
     if (id >= CSSValueXxSmall && id <= CSSValueLarger)
         validPrimitive = true;
     else
-        validPrimitive = validUnit(value, FLength | FPercent | FNonNeg);
+        validPrimitive = validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg);
     if (validPrimitive && (!m_valueList->next() || inShorthand()))
-        addProperty(CSSPropertyFontSize, parseValidPrimitive(id, value), important);
+        addProperty(CSSPropertyFontSize, parseValidPrimitive(id, valueWithCalculation), important);
     return validPrimitive;
 }
 
-bool CSSParser::parseFontVariant(bool important)
-{
-    RefPtr<CSSValueList> values;
-    if (m_valueList->size() > 1)
-        values = CSSValueList::createCommaSeparated();
-    CSSParserValue* val;
-    bool expectComma = false;
-    while ((val = m_valueList->current())) {
-        RefPtr<CSSPrimitiveValue> parsedValue;
-        if (!expectComma) {
-            expectComma = true;
-            if (val->id == CSSValueNormal || val->id == CSSValueSmallCaps)
-                parsedValue = cssValuePool().createIdentifierValue(val->id);
-            else if (val->id == CSSValueAll && !values) {
-                // 'all' is only allowed in @font-face and with no other values. Make a value list to
-                // indicate that we are in the @font-face case.
-                values = CSSValueList::createCommaSeparated();
-                parsedValue = cssValuePool().createIdentifierValue(val->id);
-            }
-        } else if (val->unit == CSSParserValue::Operator && val->iValue == ',') {
-            expectComma = false;
-            m_valueList->next();
-            continue;
-        }
-
-        if (!parsedValue)
-            return false;
-
-        m_valueList->next();
-
-        if (values)
-            values->append(parsedValue.release());
-        else {
-            addProperty(CSSPropertyFontVariant, parsedValue.release(), important);
-            return true;
-        }
-    }
-
-    if (values && values->length()) {
-        m_hasFontFaceOnlyValues = true;
-        addProperty(CSSPropertyFontVariant, values.release(), important);
-        return true;
-    }
-
-    return false;
-}
-
 static CSSValueID createFontWeightValueKeyword(int weight)
 {
     ASSERT(!(weight % 100) && weight >= 100 && weight <= 900);
@@ -5644,37 +7053,73 @@ static CSSValueID createFontWeightValueKeyword(int weight)
 
 bool CSSParser::parseFontWeight(bool important)
 {
-    CSSParserValue* value = m_valueList->current();
-    if ((value->id >= CSSValueNormal) && (value->id <= CSSValue900)) {
-        addProperty(CSSPropertyFontWeight, cssValuePool().createIdentifierValue(value->id), important);
+    CSSParserValue& value = *m_valueList->current();
+    if ((value.id >= CSSValueNormal) && (value.id <= CSSValue900)) {
+        addProperty(CSSPropertyFontWeight, CSSValuePool::singleton().createIdentifierValue(value.id), important);
         return true;
     }
-    if (validUnit(value, FInteger | FNonNeg, CSSQuirksMode)) {
-        int weight = static_cast<int>(value->fValue);
+    ValueWithCalculation valueWithCalculation(value);
+    if (validateUnit(valueWithCalculation, FInteger | FNonNeg, CSSQuirksMode)) {
+        int weight = static_cast<int>(parsedDouble(valueWithCalculation));
         if (!(weight % 100) && weight >= 100 && weight <= 900) {
-            addProperty(CSSPropertyFontWeight, cssValuePool().createIdentifierValue(createFontWeightValueKeyword(weight)), important);
+            addProperty(CSSPropertyFontWeight, CSSValuePool::singleton().createIdentifierValue(createFontWeightValueKeyword(weight)), important);
             return true;
         }
     }
     return false;
 }
 
-bool CSSParser::parseFontFaceSrcURI(CSSValueList* valueList)
+bool CSSParser::parseFontSynthesis(bool important)
+{
+    // none | [ weight || style ]
+    CSSParserValue* value = m_valueList->current();
+    if (value && value->id == CSSValueNone) {
+        addProperty(CSSPropertyFontSynthesis, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
+        m_valueList->next();
+        return true;
+    }
+
+    bool encounteredWeight = false;
+    bool encounteredStyle = false;
+    while (value) {
+        switch (value->id) {
+        case CSSValueWeight:
+            encounteredWeight = true;
+            break;
+        case CSSValueStyle:
+            encounteredStyle = true;
+            break;
+        default:
+            return false;
+        }
+        value = m_valueList->next();
+    }
+
+    RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+    if (encounteredWeight)
+        list->append(CSSValuePool::singleton().createIdentifierValue(CSSValueWeight));
+    if (encounteredStyle)
+        list->append(CSSValuePool::singleton().createIdentifierValue(CSSValueStyle));
+    addProperty(CSSPropertyFontSynthesis, list.release(), important);
+    return true;
+}
+
+bool CSSParser::parseFontFaceSrcURI(CSSValueList& valueList)
 {
     RefPtr<CSSFontFaceSrcValue> uriValue(CSSFontFaceSrcValue::create(completeURL(m_valueList->current()->string)));
 
     CSSParserValue* value = m_valueList->next();
     if (!value) {
-        valueList->append(uriValue.release());
+        valueList.append(uriValue.releaseNonNull());
         return true;
     }
     if (value->unit == CSSParserValue::Operator && value->iValue == ',') {
         m_valueList->next();
-        valueList->append(uriValue.release());
+        valueList.append(uriValue.releaseNonNull());
         return true;
     }
 
-    if (value->unit != CSSParserValue::Function || !equalIgnoringCase(value->function->name, "format("))
+    if (value->unit != CSSParserValue::Function || !equalLettersIgnoringASCIICase(value->function->name, "format("))
         return false;
 
     // FIXME: http://www.w3.org/TR/2011/WD-css3-fonts-20111004/ says that format() contains a comma-separated list of strings,
@@ -5683,21 +7128,21 @@ bool CSSParser::parseFontFaceSrcURI(CSSValueList* valueList)
     if (!args || args->size() != 1 || (args->current()->unit != CSSPrimitiveValue::CSS_STRING && args->current()->unit != CSSPrimitiveValue::CSS_IDENT))
         return false;
     uriValue->setFormat(args->current()->string);
-    valueList->append(uriValue.release());
+    valueList.append(uriValue.releaseNonNull());
     value = m_valueList->next();
     if (value && value->unit == CSSParserValue::Operator && value->iValue == ',')
         m_valueList->next();
     return true;
 }
 
-bool CSSParser::parseFontFaceSrcLocal(CSSValueList* valueList)
+bool CSSParser::parseFontFaceSrcLocal(CSSValueList& valueList)
 {
     CSSParserValueList* args = m_valueList->current()->function->args.get();
     if (!args || !args->size())
         return false;
 
     if (args->size() == 1 && args->current()->unit == CSSPrimitiveValue::CSS_STRING)
-        valueList->append(CSSFontFaceSrcValue::createLocal(args->current()->string));
+        valueList.append(CSSFontFaceSrcValue::createLocal(args->current()->string));
     else if (args->current()->unit == CSSPrimitiveValue::CSS_IDENT) {
         StringBuilder builder;
         for (CSSParserValue* localValue = args->current(); localValue; localValue = args->next()) {
@@ -5707,7 +7152,7 @@ bool CSSParser::parseFontFaceSrcLocal(CSSValueList* valueList)
                 builder.append(' ');
             builder.append(localValue->string);
         }
-        valueList->append(CSSFontFaceSrcValue::createLocal(builder.toString()));
+        valueList.append(CSSFontFaceSrcValue::createLocal(builder.toString()));
     } else
         return false;
 
@@ -5724,10 +7169,10 @@ bool CSSParser::parseFontFaceSrc()
 
     while (CSSParserValue* value = m_valueList->current()) {
         if (value->unit == CSSPrimitiveValue::CSS_URI) {
-            if (!parseFontFaceSrcURI(values.get()))
+            if (!parseFontFaceSrcURI(*values))
                 return false;
-        } else if (value->unit == CSSParserValue::Function && equalIgnoringCase(value->function->name, "local(")) {
-            if (!parseFontFaceSrcLocal(values.get()))
+        } else if (value->unit == CSSParserValue::Function && equalLettersIgnoringASCIICase(value->function->name, "local(")) {
+            if (!parseFontFaceSrcLocal(*values))
                 return false;
         } else
             return false;
@@ -6145,83 +7590,78 @@ bool CSSParser::fastParseColor(RGBA32& rgb, const StringType& name, bool strict)
     return false;
 }
     
-inline double CSSParser::parsedDouble(CSSParserValue *v, ReleaseParsedCalcValueCondition releaseCalc)
+inline double CSSParser::parsedDouble(ValueWithCalculation& valueWithCalculation)
 {
-    const double result = m_parsedCalculation ? m_parsedCalculation->doubleValue() : v->fValue;
-    if (releaseCalc == ReleaseParsedCalcValue)
-        m_parsedCalculation.release();
-    return result;
+    return valueWithCalculation.calculation() ? valueWithCalculation.calculation()->doubleValue() : valueWithCalculation.value().fValue;
 }
 
-bool CSSParser::isCalculation(CSSParserValue* value) 
+bool CSSParser::isCalculation(CSSParserValue& value)
 {
-    return (value->unit == CSSParserValue::Function) 
-        && (equalIgnoringCase(value->function->name, "calc(")
-            || equalIgnoringCase(value->function->name, "-webkit-calc(")
-            || equalIgnoringCase(value->function->name, "-webkit-min(")
-            || equalIgnoringCase(value->function->name, "-webkit-max("));
+    return value.unit == CSSParserValue::Function
+        && (equalLettersIgnoringASCIICase(value.function->name, "calc(")
+            || equalLettersIgnoringASCIICase(value.function->name, "-webkit-calc("));
 }
 
-inline int CSSParser::colorIntFromValue(CSSParserValue* v)
+inline int CSSParser::colorIntFromValue(ValueWithCalculation& valueWithCalculation)
 {
     bool isPercent;
     
-    if (m_parsedCalculation)
-        isPercent = m_parsedCalculation->category() == CalcPercent;
+    if (valueWithCalculation.calculation())
+        isPercent = valueWithCalculation.calculation()->category() == CalcPercent;
     else
-        isPercent = v->unit == CSSPrimitiveValue::CSS_PERCENTAGE;
+        isPercent = valueWithCalculation.value().unit == CSSPrimitiveValue::CSS_PERCENTAGE;
 
-    const double value = parsedDouble(v, ReleaseParsedCalcValue);
+    const double doubleValue = parsedDouble(valueWithCalculation);
     
-    if (value <= 0.0)
+    if (doubleValue <= 0.0)
         return 0;
 
     if (isPercent) {
-        if (value >= 100.0)
+        if (doubleValue >= 100.0)
             return 255;
-        return static_cast<int>(value * 256.0 / 100.0);
+        return static_cast<int>(doubleValue * 256.0 / 100.0);
     }
 
-    if (value >= 255.0)
+    if (doubleValue >= 255.0)
         return 255;
 
-    return static_cast<int>(value);
+    return static_cast<int>(doubleValue);
 }
 
-bool CSSParser::parseColorParameters(CSSParserValue* value, int* colorArray, bool parseAlpha)
+bool CSSParser::parseColorParameters(CSSParserValue& value, int* colorArray, bool parseAlpha)
 {
-    CSSParserValueList* args = value->function->args.get();
-    CSSParserValue* v = args->current();
+    CSSParserValueList* args = value.function->args.get();
+    ValueWithCalculation firstArgumentWithCalculation(*args->current());
     Units unitType = FUnknown;
     // Get the first value and its type
-    if (validUnit(v, FInteger, CSSStrictMode))
+    if (validateUnit(firstArgumentWithCalculation, FInteger, CSSStrictMode))
         unitType = FInteger;
-    else if (validUnit(v, FPercent, CSSStrictMode))
+    else if (validateUnit(firstArgumentWithCalculation, FPercent, CSSStrictMode))
         unitType = FPercent;
     else
         return false;
     
-    colorArray[0] = colorIntFromValue(v);
+    colorArray[0] = colorIntFromValue(firstArgumentWithCalculation);
     for (int i = 1; i < 3; i++) {
-        v = args->next();
-        if (v->unit != CSSParserValue::Operator && v->iValue != ',')
+        CSSParserValue& operatorArgument = *args->next();
+        if (operatorArgument.unit != CSSParserValue::Operator && operatorArgument.iValue != ',')
             return false;
-        v = args->next();
-        if (!validUnit(v, unitType, CSSStrictMode))
+        ValueWithCalculation argumentWithCalculation(*args->next());
+        if (!validateUnit(argumentWithCalculation, unitType, CSSStrictMode))
             return false;
-        colorArray[i] = colorIntFromValue(v);
+        colorArray[i] = colorIntFromValue(argumentWithCalculation);
     }
     if (parseAlpha) {
-        v = args->next();
-        if (v->unit != CSSParserValue::Operator && v->iValue != ',')
+        CSSParserValue& operatorArgument = *args->next();
+        if (operatorArgument.unit != CSSParserValue::Operator && operatorArgument.iValue != ',')
             return false;
-        v = args->next();
-        if (!validUnit(v, FNumber, CSSStrictMode))
+        ValueWithCalculation argumentWithCalculation(*args->next());
+        if (!validateUnit(argumentWithCalculation, FNumber, CSSStrictMode))
             return false;
-        const double value = parsedDouble(v, ReleaseParsedCalcValue);
+        double doubleValue = parsedDouble(argumentWithCalculation);
         // Convert the floating pointer number of alpha to an integer in the range [0, 256),
         // with an equal distribution across all 256 values.
-        colorArray[3] = static_cast<int>(max(0.0, min(1.0, value)) * nextafter(256.0, 0.0));
+        colorArray[3] = static_cast<int>(std::max<double>(0, std::min<double>(1, doubleValue)) * nextafter(256.0, 0.0));
     }
     return true;
 }
@@ -6231,86 +7671,86 @@ bool CSSParser::parseColorParameters(CSSParserValue* value, int* colorArray, boo
 // and with alpha, the format is
 // hsla(<number>, <percent>, <percent>, <number>)
 // The first value, HUE, is in an angle with a value between 0 and 360
-bool CSSParser::parseHSLParameters(CSSParserValue* value, double* colorArray, bool parseAlpha)
+bool CSSParser::parseHSLParameters(CSSParserValue& value, double* colorArray, bool parseAlpha)
 {
-    CSSParserValueList* args = value->function->args.get();
-    CSSParserValue* v = args->current();
+    CSSParserValueList* args = value.function->args.get();
+    ValueWithCalculation firstArgumentWithCalculation(*args->current());
     // Get the first value
-    if (!validUnit(v, FNumber, CSSStrictMode))
+    if (!validateUnit(firstArgumentWithCalculation, FNumber, CSSStrictMode))
         return false;
     // normalize the Hue value and change it to be between 0 and 1.0
-    colorArray[0] = (((static_cast<int>(parsedDouble(v, ReleaseParsedCalcValue)) % 360) + 360) % 360) / 360.0;
-    for (int i = 1; i < 3; i++) {
-        v = args->next();
-        if (v->unit != CSSParserValue::Operator && v->iValue != ',')
+    colorArray[0] = (((static_cast<int>(parsedDouble(firstArgumentWithCalculation)) % 360) + 360) % 360) / 360.0;
+    for (int i = 1; i < 3; ++i) {
+        CSSParserValue& operatorArgument = *args->next();
+        if (operatorArgument.unit != CSSParserValue::Operator && operatorArgument.iValue != ',')
             return false;
-        v = args->next();
-        if (!validUnit(v, FPercent, CSSStrictMode))
+        ValueWithCalculation argumentWithCalculation(*args->next());
+        if (!validateUnit(argumentWithCalculation, FPercent, CSSStrictMode))
             return false;
-        colorArray[i] = max(0.0, min(100.0, parsedDouble(v, ReleaseParsedCalcValue))) / 100.0; // needs to be value between 0 and 1.0
+        colorArray[i] = std::max<double>(0, std::min<double>(100, parsedDouble(argumentWithCalculation))) / 100.0; // needs to be value between 0 and 1.0
     }
     if (parseAlpha) {
-        v = args->next();
-        if (v->unit != CSSParserValue::Operator && v->iValue != ',')
+        CSSParserValue& operatorArgument = *args->next();
+        if (operatorArgument.unit != CSSParserValue::Operator && operatorArgument.iValue != ',')
             return false;
-        v = args->next();
-        if (!validUnit(v, FNumber, CSSStrictMode))
+        ValueWithCalculation argumentWithCalculation(*args->next());
+        if (!validateUnit(argumentWithCalculation, FNumber, CSSStrictMode))
             return false;
-        colorArray[3] = max(0.0, min(1.0, parsedDouble(v, ReleaseParsedCalcValue)));
+        colorArray[3] = std::max<double>(0, std::min<double>(1, parsedDouble(argumentWithCalculation)));
     }
     return true;
 }
 
-PassRefPtr<CSSPrimitiveValue> CSSParser::parseColor(CSSParserValue* value)
+RefPtr<CSSPrimitiveValue> CSSParser::parseColor(CSSParserValue* value)
 {
     RGBA32 c = Color::transparent;
-    if (!parseColorFromValue(value ? value : m_valueList->current(), c))
-        return 0;
-    return cssValuePool().createColorValue(c);
+    if (!parseColorFromValue(value ? *value : *m_valueList->current(), c))
+        return nullptr;
+    return CSSValuePool::singleton().createColorValue(c);
 }
 
-bool CSSParser::parseColorFromValue(CSSParserValue* value, RGBA32& c)
+bool CSSParser::parseColorFromValue(CSSParserValue& value, RGBA32& c)
 {
-    if (inQuirksMode() && value->unit == CSSPrimitiveValue::CSS_NUMBER
-        && value->fValue >= 0. && value->fValue < 1000000.) {
-        String str = String::format("%06d", static_cast<int>((value->fValue+.5)));
+    if (inQuirksMode() && value.unit == CSSPrimitiveValue::CSS_NUMBER
+        && value.fValue >= 0. && value.fValue < 1000000.) {
+        String str = String::format("%06d", static_cast<int>((value.fValue+.5)));
         // FIXME: This should be strict parsing for SVG as well.
         if (!fastParseColor(c, str, inStrictMode()))
             return false;
-    } else if (value->unit == CSSPrimitiveValue::CSS_PARSER_HEXCOLOR ||
-                value->unit == CSSPrimitiveValue::CSS_IDENT ||
-                (inQuirksMode() && value->unit == CSSPrimitiveValue::CSS_DIMENSION)) {
-        if (!fastParseColor(c, value->string, inStrictMode() && value->unit == CSSPrimitiveValue::CSS_IDENT))
+    } else if (value.unit == CSSPrimitiveValue::CSS_PARSER_HEXCOLOR
+        || value.unit == CSSPrimitiveValue::CSS_IDENT
+        || (inQuirksMode() && value.unit == CSSPrimitiveValue::CSS_DIMENSION)) {
+        if (!fastParseColor(c, value.string, inStrictMode() && value.unit == CSSPrimitiveValue::CSS_IDENT))
             return false;
-    } else if (value->unit == CSSParserValue::Function &&
-                value->function->args != 0 &&
-                value->function->args->size() == 5 /* rgb + two commas */ &&
-                equalIgnoringCase(value->function->name, "rgb(")) {
+    } else if (value.unit == CSSParserValue::Function
+        && value.function->args
+        && value.function->args->size() == 5 /* rgb + two commas */
+        && equalLettersIgnoringASCIICase(value.function->name, "rgb(")) {
         int colorValues[3];
         if (!parseColorParameters(value, colorValues, false))
             return false;
         c = makeRGB(colorValues[0], colorValues[1], colorValues[2]);
     } else {
-        if (value->unit == CSSParserValue::Function &&
-                value->function->args != 0 &&
-                value->function->args->size() == 7 /* rgba + three commas */ &&
-                equalIgnoringCase(value->function->name, "rgba(")) {
+        if (value.unit == CSSParserValue::Function
+            && value.function->args
+            && value.function->args->size() == 7 /* rgba + three commas */
+            && equalLettersIgnoringASCIICase(value.function->name, "rgba(")) {
             int colorValues[4];
             if (!parseColorParameters(value, colorValues, true))
                 return false;
             c = makeRGBA(colorValues[0], colorValues[1], colorValues[2], colorValues[3]);
-        } else if (value->unit == CSSParserValue::Function &&
-                    value->function->args != 0 &&
-                    value->function->args->size() == 5 /* hsl + two commas */ &&
-                    equalIgnoringCase(value->function->name, "hsl(")) {
+        } else if (value.unit == CSSParserValue::Function
+            && value.function->args
+            && value.function->args->size() == 5 /* hsl + two commas */
+            && equalLettersIgnoringASCIICase(value.function->name, "hsl(")) {
             double colorValues[3];
             if (!parseHSLParameters(value, colorValues, false))
                 return false;
             c = makeRGBAFromHSLA(colorValues[0], colorValues[1], colorValues[2], 1.0);
-        } else if (value->unit == CSSParserValue::Function &&
-                    value->function->args != 0 &&
-                    value->function->args->size() == 7 /* hsla + three commas */ &&
-                    equalIgnoringCase(value->function->name, "hsla(")) {
+        } else if (value.unit == CSSParserValue::Function
+            && value.function->args
+            && value.function->args->size() == 7 /* hsla + three commas */
+            && equalLettersIgnoringASCIICase(value.function->name, "hsla(")) {
             double colorValues[4];
             if (!parseHSLParameters(value, colorValues, true))
                 return false;
@@ -6325,7 +7765,7 @@ bool CSSParser::parseColorFromValue(CSSParserValue* value, RGBA32& c)
 // This class tracks parsing state for shadow values.  If it goes out of scope (e.g., due to an early return)
 // without the allowBreak bit being set, then it will clean up all of the objects and destroy them.
 struct ShadowParseContext {
-    ShadowParseContext(CSSPropertyID prop, CSSParser* parser)
+    ShadowParseContext(CSSPropertyID prop, CSSParser& parser)
         : property(prop)
         , m_parser(parser)
         , allowX(true)
@@ -6348,16 +7788,16 @@ struct ShadowParseContext {
                 values = CSSValueList::createCommaSeparated();
 
             // Construct the current shadow value and add it to the list.
-            values->append(ShadowValue::create(x.release(), y.release(), blur.release(), spread.release(), style.release(), color.release()));
+            values->append(CSSShadowValue::create(x.release(), y.release(), blur.release(), spread.release(), style.release(), color.release()));
         }
 
         // Now reset for the next shadow value.
-        x = 0;
-        y = 0;
-        blur = 0;
-        spread = 0;
-        style = 0;
-        color = 0;
+        x = nullptr;
+        y = nullptr;
+        blur = nullptr;
+        spread = nullptr;
+        style = nullptr;
+        color = nullptr;
 
         allowX = true;
         allowColor = true;
@@ -6368,30 +7808,30 @@ struct ShadowParseContext {
         allowStyle = property == CSSPropertyWebkitBoxShadow || property == CSSPropertyBoxShadow;
     }
 
-    void commitLength(CSSParserValue* v)
+    void commitLength(CSSParser::ValueWithCalculation& valueWithCalculation)
     {
-        RefPtr<CSSPrimitiveValue> val = m_parser->createPrimitiveNumericValue(v);
+        RefPtr<CSSPrimitiveValue> primitiveValue = m_parser.createPrimitiveNumericValue(valueWithCalculation);
 
         if (allowX) {
-            x = val.release();
+            x = primitiveValue.release();
             allowX = false;
             allowY = true;
             allowColor = false;
             allowStyle = false;
             allowBreak = false;
         } else if (allowY) {
-            y = val.release();
+            y = primitiveValue.release();
             allowY = false;
             allowBlur = true;
             allowColor = true;
             allowStyle = property == CSSPropertyWebkitBoxShadow || property == CSSPropertyBoxShadow;
             allowBreak = true;
         } else if (allowBlur) {
-            blur = val.release();
+            blur = primitiveValue.release();
             allowBlur = false;
             allowSpread = property == CSSPropertyWebkitBoxShadow || property == CSSPropertyBoxShadow;
         } else if (allowSpread) {
-            spread = val.release();
+            spread = primitiveValue.release();
             allowSpread = false;
         }
     }
@@ -6410,9 +7850,9 @@ struct ShadowParseContext {
         }
     }
 
-    void commitStyle(CSSParserValue* v)
+    void commitStyle(CSSParserValue& value)
     {
-        style = cssValuePool().createIdentifierValue(v->id);
+        style = CSSValuePool::singleton().createIdentifierValue(value.id);
         allowStyle = false;
         if (allowX)
             allowBreak = false;
@@ -6424,7 +7864,7 @@ struct ShadowParseContext {
     }
 
     CSSPropertyID property;
-    CSSParser* m_parser;
+    CSSParser& m_parser;
 
     RefPtr<CSSValueList> values;
     RefPtr<CSSPrimitiveValue> x;
@@ -6443,64 +7883,64 @@ struct ShadowParseContext {
     bool allowBreak;
 };
 
-PassRefPtr<CSSValueList> CSSParser::parseShadow(CSSParserValueList* valueList, CSSPropertyID propId)
+RefPtr<CSSValueList> CSSParser::parseShadow(CSSParserValueList& valueList, CSSPropertyID propId)
 {
-    ShadowParseContext context(propId, this);
-    CSSParserValue* val;
-    while ((val = valueList->current())) {
+    ShadowParseContext context(propId, *this);
+    CSSParserValue* value;
+    while ((value = valueList.current())) {
+        ValueWithCalculation valueWithCalculation(*value);
         // Check for a comma break first.
-        if (val->unit == CSSParserValue::Operator) {
-            if (val->iValue != ',' || !context.allowBreak)
+        if (value->unit == CSSParserValue::Operator) {
+            if (value->iValue != ',' || !context.allowBreak) {
                 // Other operators aren't legal or we aren't done with the current shadow
                 // value.  Treat as invalid.
-                return 0;
-#if ENABLE(SVG)
+                return nullptr;
+            }
             // -webkit-svg-shadow does not support multiple values.
             if (propId == CSSPropertyWebkitSvgShadow)
-                return 0;
-#endif
+                return nullptr;
             // The value is good.  Commit it.
             context.commitValue();
-        } else if (validUnit(val, FLength, CSSStrictMode)) {
+        } else if (validateUnit(valueWithCalculation, FLength, CSSStrictMode)) {
             // We required a length and didn't get one. Invalid.
             if (!context.allowLength())
-                return 0;
+                return nullptr;
 
             // Blur radius must be non-negative.
-            if (context.allowBlur && !validUnit(val, FLength | FNonNeg, CSSStrictMode))
-                return 0;
+            if (context.allowBlur && !validateUnit(valueWithCalculation, FLength | FNonNeg, CSSStrictMode))
+                return nullptr;
 
             // A length is allowed here.  Construct the value and add it.
-            context.commitLength(val);
-        } else if (val->id == CSSValueInset) {
+            context.commitLength(valueWithCalculation);
+        } else if (value->id == CSSValueInset) {
             if (!context.allowStyle)
-                return 0;
+                return nullptr;
 
-            context.commitStyle(val);
+            context.commitStyle(valueWithCalculation);
         } else {
             // The only other type of value that's ok is a color value.
             RefPtr<CSSPrimitiveValue> parsedColor;
-            bool isColor = ((val->id >= CSSValueAqua && val->id <= CSSValueWindowtext) || val->id == CSSValueMenu
-                            || (val->id >= CSSValueWebkitFocusRingColor && val->id <= CSSValueWebkitText && inQuirksMode())
-                            || val->id == CSSValueCurrentcolor);
+            bool isColor = (isValidSystemColorValue(value->id) || value->id == CSSValueMenu
+                || (value->id >= CSSValueWebkitFocusRingColor && value->id <= CSSValueWebkitText && inQuirksMode())
+                || value->id == CSSValueCurrentcolor);
             if (isColor) {
                 if (!context.allowColor)
-                    return 0;
-                parsedColor = cssValuePool().createIdentifierValue(val->id);
+                    return nullptr;
+                parsedColor = CSSValuePool::singleton().createIdentifierValue(value->id);
             }
 
             if (!parsedColor)
                 // It's not built-in. Try to parse it as a color.
-                parsedColor = parseColor(val);
+                parsedColor = parseColor(value);
 
             if (!parsedColor || !context.allowColor)
-                return 0; // This value is not a color or length and is invalid or
+                return nullptr; // This value is not a color or length and is invalid or
                           // it is a color, but a color isn't allowed at this point.
 
             context.commitColor(parsedColor.release());
         }
 
-        valueList->next();
+        valueList.next();
     }
 
     if (context.allowBreak) {
@@ -6509,7 +7949,7 @@ PassRefPtr<CSSValueList> CSSParser::parseShadow(CSSParserValueList* valueList, C
             return context.values.release();
     }
 
-    return 0;
+    return nullptr;
 }
 
 bool CSSParser::parseReflect(CSSPropertyID propId, bool important)
@@ -6517,78 +7957,74 @@ bool CSSParser::parseReflect(CSSPropertyID propId, bool important)
     // box-reflect: <direction> <offset> <mask>
 
     // Direction comes first.
-    CSSParserValue* val = m_valueList->current();
+    CSSParserValue* value = m_valueList->current();
     RefPtr<CSSPrimitiveValue> direction;
-#if ENABLE(CSS_VARIABLES)
-    if (val->unit == CSSPrimitiveValue::CSS_VARIABLE_NAME)
-        direction = createPrimitiveVariableNameValue(val);
-    else
-#endif
-    switch (val->id) {
+    switch (value->id) {
         case CSSValueAbove:
         case CSSValueBelow:
         case CSSValueLeft:
         case CSSValueRight:
-            direction = cssValuePool().createIdentifierValue(val->id);
+            direction = CSSValuePool::singleton().createIdentifierValue(value->id);
             break;
         default:
             return false;
     }
 
     // The offset comes next.
-    val = m_valueList->next();
+    value = m_valueList->next();
     RefPtr<CSSPrimitiveValue> offset;
-    if (!val)
-        offset = cssValuePool().createValue(0, CSSPrimitiveValue::CSS_PX);
+    if (!value)
+        offset = CSSValuePool::singleton().createValue(0, CSSPrimitiveValue::CSS_PX);
     else {
-        if (!validUnit(val, FLength | FPercent))
+        ValueWithCalculation valueWithCalculation(*value);
+        if (!validateUnit(valueWithCalculation, FLength | FPercent))
             return false;
-        offset = createPrimitiveNumericValue(val);
+        offset = createPrimitiveNumericValue(valueWithCalculation);
     }
 
     // Now for the mask.
     RefPtr<CSSValue> mask;
-    val = m_valueList->next();
-    if (val) {
+    value = m_valueList->next();
+    if (value) {
         if (!parseBorderImage(propId, mask))
             return false;
     }
 
-    RefPtr<CSSReflectValue> reflectValue = CSSReflectValue::create(direction.release(), offset.release(), mask.release());
-    addProperty(propId, reflectValue.release(), important);
+    addProperty(propId, CSSReflectValue::create(direction.release(), offset.release(), mask.release()), important);
     m_valueList->next();
     return true;
 }
 
-bool CSSParser::parseFlex(CSSParserValueList* args, bool important)
+bool CSSParser::parseFlex(CSSParserValueList& args, bool important)
 {
-    if (!args || !args->size() || args->size() > 3)
+    if (!args.size() || args.size() > 3)
         return false;
     static const double unsetValue = -1;
     double flexGrow = unsetValue;
     double flexShrink = unsetValue;
     RefPtr<CSSPrimitiveValue> flexBasis;
 
-    while (CSSParserValue* arg = args->current()) {
-        if (validUnit(arg, FNumber | FNonNeg)) {
+    while (CSSParserValue* argument = args.current()) {
+        ValueWithCalculation argumentWithCalculation(*argument);
+        if (validateUnit(argumentWithCalculation, FNumber | FNonNeg)) {
             if (flexGrow == unsetValue)
-                flexGrow = arg->fValue;
+                flexGrow = parsedDouble(argumentWithCalculation);
             else if (flexShrink == unsetValue)
-                flexShrink = arg->fValue;
-            else if (!arg->fValue) {
+                flexShrink = parsedDouble(argumentWithCalculation);
+            else if (!parsedDouble(argumentWithCalculation)) {
                 // flex only allows a basis of 0 (sans units) if flex-grow and flex-shrink values have already been set.
-                flexBasis = cssValuePool().createValue(0, CSSPrimitiveValue::CSS_PX);
+                flexBasis = CSSValuePool::singleton().createValue(0, CSSPrimitiveValue::CSS_PX);
             } else {
                 // We only allow 3 numbers without units if the last value is 0. E.g., flex:1 1 1 is invalid.
                 return false;
             }
-        } else if (!flexBasis && (arg->id == CSSValueAuto || validUnit(arg, FLength | FPercent | FNonNeg)))
-            flexBasis = parseValidPrimitive(arg->id, arg);
+        } else if (!flexBasis && (argumentWithCalculation.value().id == CSSValueAuto || validateUnit(argumentWithCalculation, FLength | FPercent | FNonNeg)))
+            flexBasis = parseValidPrimitive(argumentWithCalculation.value().id, argumentWithCalculation);
         else {
             // Not a valid arg for flex.
             return false;
         }
-        args->next();
+        args.next();
     }
 
     if (flexGrow == unsetValue)
@@ -6596,11 +8032,11 @@ bool CSSParser::parseFlex(CSSParserValueList* args, bool important)
     if (flexShrink == unsetValue)
         flexShrink = 1;
     if (!flexBasis)
-        flexBasis = cssValuePool().createValue(0, CSSPrimitiveValue::CSS_PX);
+        flexBasis = CSSValuePool::singleton().createValue(0, CSSPrimitiveValue::CSS_PX);
 
-    addProperty(CSSPropertyWebkitFlexGrow, cssValuePool().createValue(clampToFloat(flexGrow), CSSPrimitiveValue::CSS_NUMBER), important);
-    addProperty(CSSPropertyWebkitFlexShrink, cssValuePool().createValue(clampToFloat(flexShrink), CSSPrimitiveValue::CSS_NUMBER), important);
-    addProperty(CSSPropertyWebkitFlexBasis, flexBasis, important);
+    addProperty(CSSPropertyFlexGrow, CSSValuePool::singleton().createValue(clampToFloat(flexGrow), CSSPrimitiveValue::CSS_NUMBER), important);
+    addProperty(CSSPropertyFlexShrink, CSSValuePool::singleton().createValue(clampToFloat(flexShrink), CSSPrimitiveValue::CSS_NUMBER), important);
+    addProperty(CSSPropertyFlexBasis, flexBasis, important);
     return true;
 }
 
@@ -6691,7 +8127,7 @@ struct BorderImageParseContext {
         return createBorderImageValue(m_image, m_imageSlice, m_borderSlice, m_outset, m_repeat);
     }
 
-    void commitBorderImage(CSSParser* parser, bool important)
+    void commitBorderImage(CSSParser& parser, bool important)
     {
         commitBorderImageProperty(CSSPropertyBorderImageSource, parser, m_image, important);
         commitBorderImageProperty(CSSPropertyBorderImageSlice, parser, m_imageSlice, important);
@@ -6700,12 +8136,12 @@ struct BorderImageParseContext {
         commitBorderImageProperty(CSSPropertyBorderImageRepeat, parser, m_repeat, important);
     }
 
-    void commitBorderImageProperty(CSSPropertyID propId, CSSParser* parser, PassRefPtr<CSSValue> value, bool important)
+    void commitBorderImageProperty(CSSPropertyID propId, CSSParser& parser, PassRefPtr<CSSValue> value, bool important)
     {
         if (value)
-            parser->addProperty(propId, value, important);
+            parser.addProperty(propId, value, important);
         else
-            parser->addProperty(propId, cssValuePool().createImplicitInitialValue(), important, true);
+            parser.addProperty(propId, CSSValuePool::singleton().createImplicitInitialValue(), important, true);
     }
 
     bool m_canAdvance;
@@ -6731,31 +8167,31 @@ bool CSSParser::parseBorderImage(CSSPropertyID propId, RefPtr<CSSValue>& result,
 {
     ShorthandScope scope(this, propId);
     BorderImageParseContext context;
-    while (CSSParserValue* val = m_valueList->current()) {
+    while (CSSParserValue* currentValue = m_valueList->current()) {
         context.setCanAdvance(false);
 
-        if (!context.canAdvance() && context.allowForwardSlashOperator() && isForwardSlashOperator(val))
+        if (!context.canAdvance() && context.allowForwardSlashOperator() && isForwardSlashOperator(*currentValue))
             context.commitForwardSlashOperator();
 
         if (!context.canAdvance() && context.allowImage()) {
-            if (val->unit == CSSPrimitiveValue::CSS_URI)
-                context.commitImage(CSSImageValue::create(completeURL(val->string)));
-            else if (isGeneratedImageValue(val)) {
+            if (currentValue->unit == CSSPrimitiveValue::CSS_URI)
+                context.commitImage(CSSImageValue::create(completeURL(currentValue->string)));
+            else if (isGeneratedImageValue(*currentValue)) {
                 RefPtr<CSSValue> value;
-                if (parseGeneratedImage(m_valueList.get(), value))
+                if (parseGeneratedImage(*m_valueList, value))
                     context.commitImage(value.release());
                 else
                     return false;
 #if ENABLE(CSS_IMAGE_SET)
-            } else if (val->unit == CSSParserValue::Function && equalIgnoringCase(val->function->name, "-webkit-image-set(")) {
+            } else if (currentValue->unit == CSSParserValue::Function && equalLettersIgnoringASCIICase(currentValue->function->name, "-webkit-image-set(")) {
                 RefPtr<CSSValue> value = parseImageSet();
                 if (value)
                     context.commitImage(value.release());
                 else
                     return false;
 #endif
-            } else if (val->id == CSSValueNone)
-                context.commitImage(cssValuePool().createIdentifierValue(CSSValueNone));
+            } else if (currentValue->id == CSSValueNone)
+                context.commitImage(CSSValuePool::singleton().createIdentifierValue(CSSValueNone));
         }
 
         if (!context.canAdvance() && context.allowImageSlice()) {
@@ -6790,7 +8226,7 @@ bool CSSParser::parseBorderImage(CSSPropertyID propId, RefPtr<CSSValue>& result,
 
     if (context.allowCommit()) {
         if (propId == CSSPropertyBorderImage)
-            context.commitBorderImage(this, important);
+            context.commitBorderImage(*this, important);
         else
             // Need to fully commit as a single value.
             result = context.commitWebKitBorderImage();
@@ -6813,14 +8249,14 @@ bool CSSParser::parseBorderImageRepeat(RefPtr<CSSValue>& result)
     if (!val)
         return false;
     if (isBorderImageRepeatKeyword(val->id))
-        firstValue = cssValuePool().createIdentifierValue(val->id);
+        firstValue = CSSValuePool::singleton().createIdentifierValue(val->id);
     else
         return false;
 
     val = m_valueList->next();
     if (val) {
         if (isBorderImageRepeatKeyword(val->id))
-            secondValue = cssValuePool().createIdentifierValue(val->id);
+            secondValue = CSSValuePool::singleton().createIdentifierValue(val->id);
         else if (!inShorthand()) {
             // If we're not parsing a shorthand then we are invalid.
             return false;
@@ -6833,13 +8269,13 @@ bool CSSParser::parseBorderImageRepeat(RefPtr<CSSValue>& result)
     } else
         secondValue = firstValue;
 
-    result = createPrimitiveValuePair(firstValue, secondValue);
+    result = createPrimitiveValuePair(WTFMove(firstValue), WTFMove(secondValue));
     return true;
 }
 
 class BorderImageSliceParseContext {
 public:
-    BorderImageSliceParseContext(CSSParser* parser)
+    BorderImageSliceParseContext(CSSParser& parser)
     : m_parser(parser)
     , m_allowNumber(true)
     , m_allowFill(true)
@@ -6852,18 +8288,18 @@ public:
     bool allowFinalCommit() const { return m_allowFinalCommit; }
     CSSPrimitiveValue* top() const { return m_top.get(); }
 
-    void commitNumber(CSSParserValue* v)
+    void commitNumber(CSSParser::ValueWithCalculation& valueWithCalculation)
     {
-        RefPtr<CSSPrimitiveValue> val = m_parser->createPrimitiveNumericValue(v);
+        RefPtr<CSSPrimitiveValue> primitiveValue = m_parser.createPrimitiveNumericValue(valueWithCalculation);
         if (!m_top)
-            m_top = val;
+            m_top = primitiveValue.release();
         else if (!m_right)
-            m_right = val;
+            m_right = primitiveValue.release();
         else if (!m_bottom)
-            m_bottom = val;
+            m_bottom = primitiveValue.release();
         else {
             ASSERT(!m_left);
-            m_left = val;
+            m_left = primitiveValue.release();
         }
 
         m_allowNumber = !m_left;
@@ -6889,18 +8325,18 @@ public:
             m_left = m_right;
 
         // Now build a rect value to hold all four of our primitive values.
-        RefPtr<Quad> quad = Quad::create();
+        auto quad = Quad::create();
         quad->setTop(m_top);
         quad->setRight(m_right);
         quad->setBottom(m_bottom);
         quad->setLeft(m_left);
 
         // Make our new border image value now.
-        return CSSBorderImageSliceValue::create(cssValuePool().createValue(quad.release()), m_fill);
+        return CSSBorderImageSliceValue::create(CSSValuePool::singleton().createValue(WTFMove(quad)), m_fill);
     }
 
 private:
-    CSSParser* m_parser;
+    CSSParser& m_parser;
 
     bool m_allowNumber;
     bool m_allowFill;
@@ -6916,13 +8352,14 @@ private:
 
 bool CSSParser::parseBorderImageSlice(CSSPropertyID propId, RefPtr<CSSBorderImageSliceValue>& result)
 {
-    BorderImageSliceParseContext context(this);
-    CSSParserValue* val;
-    while ((val = m_valueList->current())) {
+    BorderImageSliceParseContext context(*this);
+    CSSParserValue* value;
+    while ((value = m_valueList->current())) {
+        ValueWithCalculation valueWithCalculation(*value);
         // FIXME calc() http://webkit.org/b/16662 : calc is parsed but values are not created yet.
-        if (context.allowNumber() && !isCalculation(val) && validUnit(val, FInteger | FNonNeg | FPercent, CSSStrictMode)) {
-            context.commitNumber(val);
-        } else if (context.allowFill() && val->id == CSSValueFill)
+        if (context.allowNumber() && !isCalculation(valueWithCalculation) && validateUnit(valueWithCalculation, FInteger | FNonNeg | FPercent, CSSStrictMode)) {
+            context.commitNumber(valueWithCalculation);
+        } else if (context.allowFill() && value->id == CSSValueFill)
             context.commitFill();
         else if (!inShorthand()) {
             // If we're not parsing a shorthand then we are invalid.
@@ -6953,7 +8390,7 @@ bool CSSParser::parseBorderImageSlice(CSSPropertyID propId, RefPtr<CSSBorderImag
 
 class BorderImageQuadParseContext {
 public:
-    BorderImageQuadParseContext(CSSParser* parser)
+    BorderImageQuadParseContext(CSSParser& parser)
     : m_parser(parser)
     , m_allowNumber(true)
     , m_allowFinalCommit(false)
@@ -6963,23 +8400,23 @@ public:
     bool allowFinalCommit() const { return m_allowFinalCommit; }
     CSSPrimitiveValue* top() const { return m_top.get(); }
 
-    void commitNumber(CSSParserValue* v)
+    void commitNumber(CSSParser::ValueWithCalculation& valueWithCalculation)
     {
-        RefPtr<CSSPrimitiveValue> val;
-        if (v->id == CSSValueAuto)
-            val = cssValuePool().createIdentifierValue(v->id);
+        RefPtr<CSSPrimitiveValue> primitiveValue;
+        if (valueWithCalculation.value().id == CSSValueAuto)
+            primitiveValue = CSSValuePool::singleton().createIdentifierValue(valueWithCalculation.value().id);
         else
-            val = m_parser->createPrimitiveNumericValue(v);
+            primitiveValue = m_parser.createPrimitiveNumericValue(valueWithCalculation);
 
         if (!m_top)
-            m_top = val;
+            m_top = primitiveValue.release();
         else if (!m_right)
-            m_right = val;
+            m_right = primitiveValue.release();
         else if (!m_bottom)
-            m_bottom = val;
+            m_bottom = primitiveValue.release();
         else {
             ASSERT(!m_left);
-            m_left = val;
+            m_left = primitiveValue.release();
         }
 
         m_allowNumber = !m_left;
@@ -7006,18 +8443,18 @@ public:
             m_left = m_right;
 
         // Now build a quad value to hold all four of our primitive values.
-        RefPtr<Quad> quad = Quad::create();
+        auto quad = Quad::create();
         quad->setTop(m_top);
         quad->setRight(m_right);
         quad->setBottom(m_bottom);
         quad->setLeft(m_left);
 
         // Make our new value now.
-        return cssValuePool().createValue(quad.release());
+        return CSSValuePool::singleton().createValue(WTFMove(quad));
     }
 
 private:
-    CSSParser* m_parser;
+    CSSParser& m_parser;
 
     bool m_allowNumber;
     bool m_allowFinalCommit;
@@ -7030,11 +8467,12 @@ private:
 
 bool CSSParser::parseBorderImageQuad(Units validUnits, RefPtr<CSSPrimitiveValue>& result)
 {
-    BorderImageQuadParseContext context(this);
-    CSSParserValue* val;
-    while ((val = m_valueList->current())) {
-        if (context.allowNumber() && (validUnit(val, validUnits, CSSStrictMode) || val->id == CSSValueAuto)) {
-            context.commitNumber(val);
+    BorderImageQuadParseContext context(*this);
+    CSSParserValue* value;
+    while ((value = m_valueList->current())) {
+        ValueWithCalculation valueWithCalculation(*value);
+        if (context.allowNumber() && (validateUnit(valueWithCalculation, validUnits, CSSStrictMode) || value->id == CSSValueAuto)) {
+            context.commitNumber(valueWithCalculation);
         } else if (!inShorthand()) {
             // If we're not parsing a shorthand then we are invalid.
             return false;
@@ -7064,18 +8502,6 @@ bool CSSParser::parseBorderImageOutset(RefPtr<CSSPrimitiveValue>& result)
     return parseBorderImageQuad(FLength | FInteger | FNonNeg, result);
 }
 
-static void completeBorderRadii(RefPtr<CSSPrimitiveValue> radii[4])
-{
-    if (radii[3])
-        return;
-    if (!radii[2]) {
-        if (!radii[1])
-            radii[1] = radii[0];
-        radii[2] = radii[0];
-    }
-    radii[3] = radii[1];
-}
-
 bool CSSParser::parseBorderRadius(CSSPropertyID propId, bool important)
 {
     unsigned num = m_valueList->size();
@@ -7087,9 +8513,9 @@ bool CSSParser::parseBorderRadius(CSSPropertyID propId, bool important)
 
     unsigned indexAfterSlash = 0;
     for (unsigned i = 0; i < num; ++i) {
-        CSSParserValue* value = m_valueList->valueAt(i);
-        if (value->unit == CSSParserValue::Operator) {
-            if (value->iValue != '/')
+        CSSParserValue& value = *m_valueList->valueAt(i);
+        if (value.unit == CSSParserValue::Operator) {
+            if (value.iValue != '/')
                 return false;
 
             if (!i || indexAfterSlash || i + 1 == num || num > i + 5)
@@ -7103,10 +8529,11 @@ bool CSSParser::parseBorderRadius(CSSPropertyID propId, bool important)
         if (i - indexAfterSlash >= 4)
             return false;
 
-        if (!validUnit(value, FLength | FPercent | FNonNeg))
+        ValueWithCalculation valueWithCalculation(value);
+        if (!validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg))
             return false;
 
-        RefPtr<CSSPrimitiveValue> radius = createPrimitiveNumericValue(value);
+        RefPtr<CSSPrimitiveValue> radius = createPrimitiveNumericValue(valueWithCalculation);
 
         if (!indexAfterSlash) {
             radii[0][i] = radius;
@@ -7127,7 +8554,7 @@ bool CSSParser::parseBorderRadius(CSSPropertyID propId, bool important)
     } else
         completeBorderRadii(radii[1]);
 
-    ImplicitScope implicitScope(this, PropertyImplicit);
+    ImplicitScope implicitScope(*this, PropertyImplicit);
     addProperty(CSSPropertyBorderTopLeftRadius, createPrimitiveValuePair(radii[0][0].release(), radii[1][0].release()), important);
     addProperty(CSSPropertyBorderTopRightRadius, createPrimitiveValuePair(radii[0][1].release(), radii[1][1].release()), important);
     addProperty(CSSPropertyBorderBottomRightRadius, createPrimitiveValuePair(radii[0][2].release(), radii[1][2].release()), important);
@@ -7138,28 +8565,32 @@ bool CSSParser::parseBorderRadius(CSSPropertyID propId, bool important)
 bool CSSParser::parseAspectRatio(bool important)
 {
     unsigned num = m_valueList->size();
-    if (num == 1 && m_valueList->valueAt(0)->id == CSSValueNone) {
-        addProperty(CSSPropertyWebkitAspectRatio, cssValuePool().createIdentifierValue(CSSValueNone), important);
-        return true;
+    if (num == 1) {
+        CSSValueID valueId = m_valueList->valueAt(0)->id;
+        if (valueId == CSSValueAuto || valueId == CSSValueFromDimensions || valueId == CSSValueFromIntrinsic) {
+            addProperty(CSSPropertyWebkitAspectRatio, CSSValuePool::singleton().createIdentifierValue(valueId), important);
+            return true;
+        }
     }
 
     if (num != 3)
         return false;
 
-    CSSParserValue* lvalue = m_valueList->valueAt(0);
-    CSSParserValue* op = m_valueList->valueAt(1);
-    CSSParserValue* rvalue = m_valueList->valueAt(2);
+    CSSParserValue& op = *m_valueList->valueAt(1);
 
     if (!isForwardSlashOperator(op))
         return false;
 
-    if (!validUnit(lvalue, FNumber | FNonNeg) || !validUnit(rvalue, FNumber | FNonNeg))
+    ValueWithCalculation lvalueWithCalculation(*m_valueList->valueAt(0));
+    ValueWithCalculation rvalueWithCalculation(*m_valueList->valueAt(2));
+    if (!validateUnit(lvalueWithCalculation, FNumber | FNonNeg) || !validateUnit(rvalueWithCalculation, FNumber | FNonNeg))
         return false;
 
-    if (!lvalue->fValue || !rvalue->fValue)
+    // FIXME: This doesn't handle calculated values.
+    if (!lvalueWithCalculation.value().fValue || !rvalueWithCalculation.value().fValue)
         return false;
 
-    addProperty(CSSPropertyWebkitAspectRatio, CSSAspectRatioValue::create(narrowPrecisionToFloat(lvalue->fValue), narrowPrecisionToFloat(rvalue->fValue)), important);
+    addProperty(CSSPropertyWebkitAspectRatio, CSSAspectRatioValue::create(narrowPrecisionToFloat(lvalueWithCalculation.value().fValue), narrowPrecisionToFloat(rvalueWithCalculation.value().fValue)), important);
 
     return true;
 }
@@ -7172,11 +8603,11 @@ bool CSSParser::parseCounter(CSSPropertyID propId, int defaultValue, bool import
     RefPtr<CSSPrimitiveValue> counterName;
 
     while (true) {
-        CSSParserValue* val = m_valueList->current();
+        CSSParserValue* value = m_valueList->current();
         switch (state) {
             case ID:
-                if (val && val->unit == CSSPrimitiveValue::CSS_IDENT) {
-                    counterName = createPrimitiveStringValue(val);
+                if (value && value->unit == CSSPrimitiveValue::CSS_IDENT) {
+                    counterName = createPrimitiveStringValue(*value);
                     state = VAL;
                     m_valueList->next();
                     continue;
@@ -7184,13 +8615,13 @@ bool CSSParser::parseCounter(CSSPropertyID propId, int defaultValue, bool import
                 break;
             case VAL: {
                 int i = defaultValue;
-                if (val && val->unit == CSSPrimitiveValue::CSS_NUMBER) {
-                    i = clampToInteger(val->fValue);
+                if (value && value->unit == CSSPrimitiveValue::CSS_NUMBER) {
+                    i = clampToInteger(value->fValue);
                     m_valueList->next();
                 }
 
                 list->append(createPrimitiveValuePair(counterName.release(),
-                    cssValuePool().createValue(i, CSSPrimitiveValue::CSS_NUMBER)));
+                    CSSValuePool::singleton().createValue(i, CSSPrimitiveValue::CSS_NUMBER)));
                 state = ID;
                 continue;
             }
@@ -7207,67 +8638,67 @@ bool CSSParser::parseCounter(CSSPropertyID propId, int defaultValue, bool import
 }
 
 // This should go away once we drop support for -webkit-gradient
-static PassRefPtr<CSSPrimitiveValue> parseDeprecatedGradientPoint(CSSParserValue* a, bool horizontal)
+static PassRefPtr<CSSPrimitiveValue> parseDeprecatedGradientPoint(CSSParserValue& value, bool horizontal)
 {
     RefPtr<CSSPrimitiveValue> result;
-    if (a->unit == CSSPrimitiveValue::CSS_IDENT) {
-        if ((equalIgnoringCase(a, "left") && horizontal)
-            || (equalIgnoringCase(a, "top") && !horizontal))
-            result = cssValuePool().createValue(0., CSSPrimitiveValue::CSS_PERCENTAGE);
-        else if ((equalIgnoringCase(a, "right") && horizontal)
-                 || (equalIgnoringCase(a, "bottom") && !horizontal))
-            result = cssValuePool().createValue(100., CSSPrimitiveValue::CSS_PERCENTAGE);
-        else if (equalIgnoringCase(a, "center"))
-            result = cssValuePool().createValue(50., CSSPrimitiveValue::CSS_PERCENTAGE);
-    } else if (a->unit == CSSPrimitiveValue::CSS_NUMBER || a->unit == CSSPrimitiveValue::CSS_PERCENTAGE)
-        result = cssValuePool().createValue(a->fValue, static_cast<CSSPrimitiveValue::UnitTypes>(a->unit));
+    if (value.unit == CSSPrimitiveValue::CSS_IDENT) {
+        if ((equalLettersIgnoringASCIICase(value, "left") && horizontal)
+            || (equalLettersIgnoringASCIICase(value, "top") && !horizontal))
+            result = CSSValuePool::singleton().createValue(0., CSSPrimitiveValue::CSS_PERCENTAGE);
+        else if ((equalLettersIgnoringASCIICase(value, "right") && horizontal)
+            || (equalLettersIgnoringASCIICase(value, "bottom") && !horizontal))
+            result = CSSValuePool::singleton().createValue(100., CSSPrimitiveValue::CSS_PERCENTAGE);
+        else if (equalLettersIgnoringASCIICase(value, "center"))
+            result = CSSValuePool::singleton().createValue(50., CSSPrimitiveValue::CSS_PERCENTAGE);
+    } else if (value.unit == CSSPrimitiveValue::CSS_NUMBER || value.unit == CSSPrimitiveValue::CSS_PERCENTAGE)
+        result = CSSValuePool::singleton().createValue(value.fValue, static_cast<CSSPrimitiveValue::UnitTypes>(value.unit));
     return result;
 }
 
-static bool parseDeprecatedGradientColorStop(CSSParser* p, CSSParserValue* a, CSSGradientColorStop& stop)
+static bool parseDeprecatedGradientColorStop(CSSParser& parser, CSSParserValue& value, CSSGradientColorStop& stop)
 {
-    if (a->unit != CSSParserValue::Function)
+    if (value.unit != CSSParserValue::Function)
         return false;
 
-    if (!equalIgnoringCase(a->function->name, "from(") &&
-        !equalIgnoringCase(a->function->name, "to(") &&
-        !equalIgnoringCase(a->function->name, "color-stop("))
+    if (!equalLettersIgnoringASCIICase(value.function->name, "from(")
+        && !equalLettersIgnoringASCIICase(value.function->name, "to(")
+        && !equalLettersIgnoringASCIICase(value.function->name, "color-stop("))
         return false;
 
-    CSSParserValueList* args = a->function->args.get();
+    CSSParserValueList* args = value.function->args.get();
     if (!args)
         return false;
 
-    if (equalIgnoringCase(a->function->name, "from(")
-        || equalIgnoringCase(a->function->name, "to(")) {
+    if (equalLettersIgnoringASCIICase(value.function->name, "from(")
+        || equalLettersIgnoringASCIICase(value.function->name, "to(")) {
         // The "from" and "to" stops expect 1 argument.
         if (args->size() != 1)
             return false;
 
-        if (equalIgnoringCase(a->function->name, "from("))
-            stop.m_position = cssValuePool().createValue(0, CSSPrimitiveValue::CSS_NUMBER);
+        if (equalLettersIgnoringASCIICase(value.function->name, "from("))
+            stop.m_position = CSSValuePool::singleton().createValue(0, CSSPrimitiveValue::CSS_NUMBER);
         else
-            stop.m_position = cssValuePool().createValue(1, CSSPrimitiveValue::CSS_NUMBER);
+            stop.m_position = CSSValuePool::singleton().createValue(1, CSSPrimitiveValue::CSS_NUMBER);
 
         CSSValueID id = args->current()->id;
-        if (id == CSSValueWebkitText || (id >= CSSValueAqua && id <= CSSValueWindowtext) || id == CSSValueMenu)
-            stop.m_color = cssValuePool().createIdentifierValue(id);
+        if (id == CSSValueWebkitText || CSSParser::isValidSystemColorValue(id) || id == CSSValueMenu)
+            stop.m_color = CSSValuePool::singleton().createIdentifierValue(id);
         else
-            stop.m_color = p->parseColor(args->current());
+            stop.m_color = parser.parseColor(args->current());
         if (!stop.m_color)
             return false;
     }
 
     // The "color-stop" function expects 3 arguments.
-    if (equalIgnoringCase(a->function->name, "color-stop(")) {
+    if (equalLettersIgnoringASCIICase(value.function->name, "color-stop(")) {
         if (args->size() != 3)
             return false;
 
         CSSParserValue* stopArg = args->current();
         if (stopArg->unit == CSSPrimitiveValue::CSS_PERCENTAGE)
-            stop.m_position = cssValuePool().createValue(stopArg->fValue / 100, CSSPrimitiveValue::CSS_NUMBER);
+            stop.m_position = CSSValuePool::singleton().createValue(stopArg->fValue / 100, CSSPrimitiveValue::CSS_NUMBER);
         else if (stopArg->unit == CSSPrimitiveValue::CSS_NUMBER)
-            stop.m_position = cssValuePool().createValue(stopArg->fValue, CSSPrimitiveValue::CSS_NUMBER);
+            stop.m_position = CSSValuePool::singleton().createValue(stopArg->fValue, CSSPrimitiveValue::CSS_NUMBER);
         else
             return false;
 
@@ -7277,10 +8708,10 @@ static bool parseDeprecatedGradientColorStop(CSSParser* p, CSSParserValue* a, CS
 
         stopArg = args->next();
         CSSValueID id = stopArg->id;
-        if (id == CSSValueWebkitText || (id >= CSSValueAqua && id <= CSSValueWindowtext) || id == CSSValueMenu)
-            stop.m_color = cssValuePool().createIdentifierValue(id);
+        if (id == CSSValueWebkitText || CSSParser::isValidSystemColorValue(id) || id == CSSValueMenu)
+            stop.m_color = CSSValuePool::singleton().createIdentifierValue(id);
         else
-            stop.m_color = p->parseColor(stopArg);
+            stop.m_color = parser.parseColor(stopArg);
         if (!stop.m_color)
             return false;
     }
@@ -7288,21 +8719,21 @@ static bool parseDeprecatedGradientColorStop(CSSParser* p, CSSParserValue* a, CS
     return true;
 }
 
-bool CSSParser::parseDeprecatedGradient(CSSParserValueList* valueList, RefPtr<CSSValue>& gradient)
+bool CSSParser::parseDeprecatedGradient(CSSParserValueList& valueList, RefPtr<CSSValue>& gradient)
 {
     // Walk the arguments.
-    CSSParserValueList* args = valueList->current()->function->args.get();
+    CSSParserValueList* args = valueList.current()->function->args.get();
     if (!args || args->size() == 0)
         return false;
 
     // The first argument is the gradient type.  It is an identifier.
     CSSGradientType gradientType;
-    CSSParserValue* a = args->current();
-    if (!a || a->unit != CSSPrimitiveValue::CSS_IDENT)
+    CSSParserValue* argument = args->current();
+    if (!argument || argument->unit != CSSPrimitiveValue::CSS_IDENT)
         return false;
-    if (equalIgnoringCase(a, "linear"))
+    if (equalLettersIgnoringASCIICase(*argument, "linear"))
         gradientType = CSSDeprecatedLinearGradient;
-    else if (equalIgnoringCase(a, "radial"))
+    else if (equalLettersIgnoringASCIICase(*argument, "radial"))
         gradientType = CSSDeprecatedRadialGradient;
     else
         return false;
@@ -7321,63 +8752,65 @@ bool CSSParser::parseDeprecatedGradient(CSSParserValueList* valueList, RefPtr<CS
     }
 
     // Comma.
-    a = args->next();
-    if (!isComma(a))
+    argument = args->next();
+    if (!isComma(argument))
         return false;
 
     // Next comes the starting point for the gradient as an x y pair.  There is no
     // comma between the x and the y values.
     // First X.  It can be left, right, number or percent.
-    a = args->next();
-    if (!a)
+    argument = args->next();
+    if (!argument)
         return false;
-    RefPtr<CSSPrimitiveValue> point = parseDeprecatedGradientPoint(a, true);
+    RefPtr<CSSPrimitiveValue> point = parseDeprecatedGradientPoint(*argument, true);
     if (!point)
         return false;
     result->setFirstX(point.release());
 
     // First Y.  It can be top, bottom, number or percent.
-    a = args->next();
-    if (!a)
+    argument = args->next();
+    if (!argument)
         return false;
-    point = parseDeprecatedGradientPoint(a, false);
+    point = parseDeprecatedGradientPoint(*argument, false);
     if (!point)
         return false;
     result->setFirstY(point.release());
 
     // Comma after the first point.
-    a = args->next();
-    if (!isComma(a))
+    argument = args->next();
+    if (!isComma(argument))
         return false;
 
     // For radial gradients only, we now expect a numeric radius.
     if (gradientType == CSSDeprecatedRadialGradient) {
-        a = args->next();
-        if (!a || a->unit != CSSPrimitiveValue::CSS_NUMBER)
+        argument = args->next();
+        // FIXME: This does not handle calculation values.
+        if (!argument || argument->unit != CSSPrimitiveValue::CSS_NUMBER)
             return false;
-        static_cast<CSSRadialGradientValue*>(result.get())->setFirstRadius(createPrimitiveNumericValue(a));
+        ValueWithCalculation argumentWithCalculation(*argument);
+        downcast<CSSRadialGradientValue>(*result).setFirstRadius(createPrimitiveNumericValue(argumentWithCalculation));
 
         // Comma after the first radius.
-        a = args->next();
-        if (!isComma(a))
+        argument = args->next();
+        if (!isComma(argument))
             return false;
     }
 
     // Next is the ending point for the gradient as an x, y pair.
     // Second X.  It can be left, right, number or percent.
-    a = args->next();
-    if (!a)
+    argument = args->next();
+    if (!argument)
         return false;
-    point = parseDeprecatedGradientPoint(a, true);
+    point = parseDeprecatedGradientPoint(*argument, true);
     if (!point)
         return false;
     result->setSecondX(point.release());
 
     // Second Y.  It can be top, bottom, number or percent.
-    a = args->next();
-    if (!a)
+    argument = args->next();
+    if (!argument)
         return false;
-    point = parseDeprecatedGradientPoint(a, false);
+    point = parseDeprecatedGradientPoint(*argument, false);
     if (!point)
         return false;
     result->setSecondY(point.release());
@@ -7385,48 +8818,50 @@ bool CSSParser::parseDeprecatedGradient(CSSParserValueList* valueList, RefPtr<CS
     // For radial gradients only, we now expect the second radius.
     if (gradientType == CSSDeprecatedRadialGradient) {
         // Comma after the second point.
-        a = args->next();
-        if (!isComma(a))
+        argument = args->next();
+        if (!isComma(argument))
             return false;
 
-        a = args->next();
-        if (!a || a->unit != CSSPrimitiveValue::CSS_NUMBER)
+        argument = args->next();
+        // FIXME: This does not handle calculation values.
+        if (!argument || argument->unit != CSSPrimitiveValue::CSS_NUMBER)
             return false;
-        static_cast<CSSRadialGradientValue*>(result.get())->setSecondRadius(createPrimitiveNumericValue(a));
+        ValueWithCalculation argumentWithCalculation(*argument);
+        downcast<CSSRadialGradientValue>(*result).setSecondRadius(createPrimitiveNumericValue(argumentWithCalculation));
     }
 
     // We now will accept any number of stops (0 or more).
-    a = args->next();
-    while (a) {
+    argument = args->next();
+    while (argument) {
         // Look for the comma before the next stop.
-        if (!isComma(a))
+        if (!isComma(argument))
             return false;
 
         // Now examine the stop itself.
-        a = args->next();
-        if (!a)
+        argument = args->next();
+        if (!argument)
             return false;
 
         // The function name needs to be one of "from", "to", or "color-stop."
         CSSGradientColorStop stop;
-        if (!parseDeprecatedGradientColorStop(this, a, stop))
+        if (!parseDeprecatedGradientColorStop(*this, *argument, stop))
             return false;
         result->addStop(stop);
 
         // Advance
-        a = args->next();
+        argument = args->next();
     }
 
     gradient = result.release();
     return true;
 }
 
-static PassRefPtr<CSSPrimitiveValue> valueFromSideKeyword(CSSParserValue* a, bool& isHorizontal)
+static PassRefPtr<CSSPrimitiveValue> valueFromSideKeyword(CSSParserValue& value, bool& isHorizontal)
 {
-    if (a->unit != CSSPrimitiveValue::CSS_IDENT)
-        return 0;
+    if (value.unit != CSSPrimitiveValue::CSS_IDENT)
+        return nullptr;
 
-    switch (a->id) {
+    switch (value.id) {
         case CSSValueLeft:
         case CSSValueRight:
             isHorizontal = true;
@@ -7436,37 +8871,38 @@ static PassRefPtr<CSSPrimitiveValue> valueFromSideKeyword(CSSParserValue* a, boo
             isHorizontal = false;
             break;
         default:
-            return 0;
+            return nullptr;
     }
-    return cssValuePool().createIdentifierValue(a->id);
+    return CSSValuePool::singleton().createIdentifierValue(value.id);
 }
 
-static PassRefPtr<CSSPrimitiveValue> parseGradientColorOrKeyword(CSSParser* p, CSSParserValue* value)
+static PassRefPtr<CSSPrimitiveValue> parseGradientColorOrKeyword(CSSParser& parser, CSSParserValue& value)
 {
-    CSSValueID id = value->id;
-    if (id == CSSValueWebkitText || (id >= CSSValueAqua && id <= CSSValueWindowtext) || id == CSSValueMenu || id == CSSValueCurrentcolor)
-        return cssValuePool().createIdentifierValue(id);
+    CSSValueID id = value.id;
+    if (id == CSSValueWebkitText || CSSParser::isValidSystemColorValue(id) || id == CSSValueMenu || id == CSSValueCurrentcolor)
+        return CSSValuePool::singleton().createIdentifierValue(id);
 
-    return p->parseColor(value);
+    return parser.parseColor(&value);
 }
 
-bool CSSParser::parseDeprecatedLinearGradient(CSSParserValueList* valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
+bool CSSParser::parseDeprecatedLinearGradient(CSSParserValueList& valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
 {
     RefPtr<CSSLinearGradientValue> result = CSSLinearGradientValue::create(repeating, CSSPrefixedLinearGradient);
 
     // Walk the arguments.
-    CSSParserValueList* args = valueList->current()->function->args.get();
+    CSSParserValueList* args = valueList.current()->function->args.get();
     if (!args || !args->size())
         return false;
 
-    CSSParserValue* a = args->current();
-    if (!a)
+    CSSParserValue* argument = args->current();
+    if (!argument)
         return false;
+    ValueWithCalculation argumentWithCalculation(*argument);
 
     bool expectComma = false;
     // Look for angle.
-    if (validUnit(a, FAngle, CSSStrictMode)) {
-        result->setAngle(createPrimitiveNumericValue(a));
+    if (validateUnit(argumentWithCalculation, FAngle, CSSStrictMode)) {
+        result->setAngle(createPrimitiveNumericValue(argumentWithCalculation));
 
         args->next();
         expectComma = true;
@@ -7476,14 +8912,14 @@ bool CSSParser::parseDeprecatedLinearGradient(CSSParserValueList* valueList, Ref
 
         RefPtr<CSSPrimitiveValue> location;
         bool isHorizontal = false;
-        if ((location = valueFromSideKeyword(a, isHorizontal))) {
+        if ((location = valueFromSideKeyword(*argument, isHorizontal))) {
             if (isHorizontal)
                 startX = location;
             else
                 startY = location;
 
-            if ((a = args->next())) {
-                if ((location = valueFromSideKeyword(a, isHorizontal))) {
+            if ((argument = args->next())) {
+                if ((location = valueFromSideKeyword(*argument, isHorizontal))) {
                     if (isHorizontal) {
                         if (startX)
                             return false;
@@ -7502,13 +8938,13 @@ bool CSSParser::parseDeprecatedLinearGradient(CSSParserValueList* valueList, Ref
         }
 
         if (!startX && !startY)
-            startY = cssValuePool().createIdentifierValue(CSSValueTop);
+            startY = CSSValuePool::singleton().createIdentifierValue(CSSValueTop);
 
         result->setFirstX(startX.release());
         result->setFirstY(startY.release());
     }
 
-    if (!parseGradientColorStops(args, result.get(), expectComma))
+    if (!parseGradientColorStops(*args, *result, expectComma))
         return false;
 
     if (!result->stopCount())
@@ -7518,62 +8954,59 @@ bool CSSParser::parseDeprecatedLinearGradient(CSSParserValueList* valueList, Ref
     return true;
 }
 
-bool CSSParser::parseDeprecatedRadialGradient(CSSParserValueList* valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
+bool CSSParser::parseDeprecatedRadialGradient(CSSParserValueList& valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
 {
     RefPtr<CSSRadialGradientValue> result = CSSRadialGradientValue::create(repeating, CSSPrefixedRadialGradient);
 
     // Walk the arguments.
-    CSSParserValueList* args = valueList->current()->function->args.get();
+    CSSParserValueList* args = valueList.current()->function->args.get();
     if (!args || !args->size())
         return false;
 
-    CSSParserValue* a = args->current();
-    if (!a)
+    CSSParserValue* argument = args->current();
+    if (!argument)
         return false;
 
     bool expectComma = false;
 
     // Optional background-position
-    RefPtr<CSSValue> centerX;
-    RefPtr<CSSValue> centerY;
+    RefPtr<CSSPrimitiveValue> centerX;
+    RefPtr<CSSPrimitiveValue> centerY;
     // parse2ValuesFillPosition advances the args next pointer.
-    parse2ValuesFillPosition(args, centerX, centerY);
-    a = args->current();
-    if (!a)
+    parse2ValuesFillPosition(*args, centerX, centerY);
+    argument = args->current();
+    if (!argument)
         return false;
 
     if (centerX || centerY) {
         // Comma
-        if (!isComma(a))
+        if (!isComma(argument))
             return false;
 
-        a = args->next();
-        if (!a)
+        argument = args->next();
+        if (!argument)
             return false;
     }
 
-    ASSERT(!centerX || centerX->isPrimitiveValue());
-    ASSERT(!centerY || centerY->isPrimitiveValue());
-
-    result->setFirstX(static_cast<CSSPrimitiveValue*>(centerX.get()));
-    result->setSecondX(static_cast<CSSPrimitiveValue*>(centerX.get()));
+    result->setFirstX(centerX);
+    result->setSecondX(centerX);
     // CSS3 radial gradients always share the same start and end point.
-    result->setFirstY(static_cast<CSSPrimitiveValue*>(centerY.get()));
-    result->setSecondY(static_cast<CSSPrimitiveValue*>(centerY.get()));
+    result->setFirstY(centerY);
+    result->setSecondY(centerY);
 
     RefPtr<CSSPrimitiveValue> shapeValue;
     RefPtr<CSSPrimitiveValue> sizeValue;
 
     // Optional shape and/or size in any order.
     for (int i = 0; i < 2; ++i) {
-        if (a->unit != CSSPrimitiveValue::CSS_IDENT)
+        if (argument->unit != CSSPrimitiveValue::CSS_IDENT)
             break;
 
         bool foundValue = false;
-        switch (a->id) {
+        switch (argument->id) {
         case CSSValueCircle:
         case CSSValueEllipse:
-            shapeValue = cssValuePool().createIdentifierValue(a->id);
+            shapeValue = CSSValuePool::singleton().createIdentifierValue(argument->id);
             foundValue = true;
             break;
         case CSSValueClosestSide:
@@ -7582,7 +9015,7 @@ bool CSSParser::parseDeprecatedRadialGradient(CSSParserValueList* valueList, Ref
         case CSSValueFarthestCorner:
         case CSSValueContain:
         case CSSValueCover:
-            sizeValue = cssValuePool().createIdentifierValue(a->id);
+            sizeValue = CSSValuePool::singleton().createIdentifierValue(argument->id);
             foundValue = true;
             break;
         default:
@@ -7590,8 +9023,8 @@ bool CSSParser::parseDeprecatedRadialGradient(CSSParserValueList* valueList, Ref
         }
 
         if (foundValue) {
-            a = args->next();
-            if (!a)
+            argument = args->next();
+            if (!argument)
                 return false;
 
             expectComma = true;
@@ -7606,20 +9039,22 @@ bool CSSParser::parseDeprecatedRadialGradient(CSSParserValueList* valueList, Ref
     RefPtr<CSSPrimitiveValue> verticalSize;
 
     if (!shapeValue && !sizeValue) {
-        if (validUnit(a, FLength | FPercent)) {
-            horizontalSize = createPrimitiveNumericValue(a);
-            a = args->next();
-            if (!a)
+        ValueWithCalculation hSizeWithCalculation(*argument);
+        if (validateUnit(hSizeWithCalculation, FLength | FPercent)) {
+            horizontalSize = createPrimitiveNumericValue(hSizeWithCalculation);
+            argument = args->next();
+            if (!argument)
                 return false;
 
             expectComma = true;
         }
 
-        if (validUnit(a, FLength | FPercent)) {
-            verticalSize = createPrimitiveNumericValue(a);
+        ValueWithCalculation vSizeWithCalculation(*argument);
+        if (validateUnit(vSizeWithCalculation, FLength | FPercent)) {
+            verticalSize = createPrimitiveNumericValue(vSizeWithCalculation);
 
-            a = args->next();
-            if (!a)
+            argument = args->next();
+            if (!argument)
                 return false;
             expectComma = true;
         }
@@ -7632,43 +9067,44 @@ bool CSSParser::parseDeprecatedRadialGradient(CSSParserValueList* valueList, Ref
     result->setEndHorizontalSize(horizontalSize);
     result->setEndVerticalSize(verticalSize);
 
-    if (!parseGradientColorStops(args, result.get(), expectComma))
+    if (!parseGradientColorStops(*args, *result, expectComma))
         return false;
 
     gradient = result.release();
     return true;
 }
 
-bool CSSParser::parseLinearGradient(CSSParserValueList* valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
+bool CSSParser::parseLinearGradient(CSSParserValueList& valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
 {
     RefPtr<CSSLinearGradientValue> result = CSSLinearGradientValue::create(repeating, CSSLinearGradient);
 
-    CSSParserValueList* args = valueList->current()->function->args.get();
+    CSSParserValueList* args = valueList.current()->function->args.get();
     if (!args || !args->size())
         return false;
 
-    CSSParserValue* a = args->current();
-    if (!a)
+    if (!args->current())
         return false;
 
+    ValueWithCalculation firstArgumentWithCalculation(*args->current());
+
     bool expectComma = false;
     // Look for angle.
-    if (validUnit(a, FAngle, CSSStrictMode)) {
-        result->setAngle(createPrimitiveNumericValue(a));
+    if (validateUnit(firstArgumentWithCalculation, FAngle, CSSStrictMode)) {
+        result->setAngle(createPrimitiveNumericValue(firstArgumentWithCalculation));
 
         args->next();
         expectComma = true;
-    } else if (a->unit == CSSPrimitiveValue::CSS_IDENT && equalIgnoringCase(a, "to")) {
+    } else if (firstArgumentWithCalculation.value().unit == CSSPrimitiveValue::CSS_IDENT && equalLettersIgnoringASCIICase(firstArgumentWithCalculation, "to")) {
         // to [ [left | right] || [top | bottom] ]
-        a = args->next();
-        if (!a)
+        CSSParserValue* nextArgument = args->next();
+        if (!nextArgument)
             return false;
 
         RefPtr<CSSPrimitiveValue> endX, endY;
         RefPtr<CSSPrimitiveValue> location;
         bool isHorizontal = false;
 
-        location = valueFromSideKeyword(a, isHorizontal);
+        location = valueFromSideKeyword(*nextArgument, isHorizontal);
         if (!location)
             return false;
 
@@ -7677,11 +9113,11 @@ bool CSSParser::parseLinearGradient(CSSParserValueList* valueList, RefPtr<CSSVal
         else
             endY = location;
 
-        a = args->next();
-        if (!a)
+        nextArgument = args->next();
+        if (!nextArgument)
             return false;
 
-        location = valueFromSideKeyword(a, isHorizontal);
+        location = valueFromSideKeyword(*nextArgument, isHorizontal);
         if (location) {
             if (isHorizontal) {
                 if (endX)
@@ -7701,7 +9137,7 @@ bool CSSParser::parseLinearGradient(CSSParserValueList* valueList, RefPtr<CSSVal
         result->setFirstY(endY.release());
     }
 
-    if (!parseGradientColorStops(args, result.get(), expectComma))
+    if (!parseGradientColorStops(*args, *result, expectComma))
         return false;
 
     if (!result->stopCount())
@@ -7711,16 +9147,16 @@ bool CSSParser::parseLinearGradient(CSSParserValueList* valueList, RefPtr<CSSVal
     return true;
 }
 
-bool CSSParser::parseRadialGradient(CSSParserValueList* valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
+bool CSSParser::parseRadialGradient(CSSParserValueList& valueList, RefPtr<CSSValue>& gradient, CSSGradientRepeat repeating)
 {
     RefPtr<CSSRadialGradientValue> result = CSSRadialGradientValue::create(repeating, CSSRadialGradient);
 
-    CSSParserValueList* args = valueList->current()->function->args.get();
+    CSSParserValueList* args = valueList.current()->function->args.get();
     if (!args || !args->size())
         return false;
 
-    CSSParserValue* a = args->current();
-    if (!a)
+    CSSParserValue* argument = args->current();
+    if (!argument)
         return false;
 
     bool expectComma = false;
@@ -7735,14 +9171,15 @@ bool CSSParser::parseRadialGradient(CSSParserValueList* valueList, RefPtr<CSSVal
     // [ ellipse || [ <length> | <percentage> ]{2} ] |
     // [ [ circle | ellipse] || <size-keyword> ]
     for (int i = 0; i < 3; ++i) {
-        if (a->unit == CSSPrimitiveValue::CSS_IDENT) {
+        ValueWithCalculation argumentWithCalculation(*argument);
+        if (argument->unit == CSSPrimitiveValue::CSS_IDENT) {
             bool badIdent = false;
-            switch (a->id) {
+            switch (argument->id) {
             case CSSValueCircle:
             case CSSValueEllipse:
                 if (shapeValue)
                     return false;
-                shapeValue = cssValuePool().createIdentifierValue(a->id);
+                shapeValue = CSSValuePool::singleton().createIdentifierValue(argument->id);
                 break;
             case CSSValueClosestSide:
             case CSSValueClosestCorner:
@@ -7750,7 +9187,7 @@ bool CSSParser::parseRadialGradient(CSSParserValueList* valueList, RefPtr<CSSVal
             case CSSValueFarthestCorner:
                 if (sizeValue || horizontalSize)
                     return false;
-                sizeValue = cssValuePool().createIdentifierValue(a->id);
+                sizeValue = CSSValuePool::singleton().createIdentifierValue(argument->id);
                 break;
             default:
                 badIdent = true;
@@ -7759,24 +9196,25 @@ bool CSSParser::parseRadialGradient(CSSParserValueList* valueList, RefPtr<CSSVal
             if (badIdent)
                 break;
 
-            a = args->next();
-            if (!a)
+            argument = args->next();
+            if (!argument)
                 return false;
-        } else if (validUnit(a, FLength | FPercent)) {
+        } else if (validateUnit(argumentWithCalculation, FLength | FPercent)) {
 
             if (sizeValue || horizontalSize)
                 return false;
-            horizontalSize = createPrimitiveNumericValue(a);
+            horizontalSize = createPrimitiveNumericValue(argumentWithCalculation);
 
-            a = args->next();
-            if (!a)
+            argument = args->next();
+            if (!argument)
                 return false;
 
-            if (validUnit(a, FLength | FPercent)) {
-                verticalSize = createPrimitiveNumericValue(a);
+            ValueWithCalculation vSizeWithCalculation(*argument);
+            if (validateUnit(vSizeWithCalculation, FLength | FPercent)) {
+                verticalSize = createPrimitiveNumericValue(vSizeWithCalculation);
                 ++i;
-                a = args->next();
-                if (!a)
+                argument = args->next();
+                if (!argument)
                     return false;
             }
         } else
@@ -7803,179 +9241,241 @@ bool CSSParser::parseRadialGradient(CSSParserValueList* valueList, RefPtr<CSSVal
 
     // Second part of grammar, the center-position clause:
     // at <position>
-    RefPtr<CSSValue> centerX;
-    RefPtr<CSSValue> centerY;
-    if (a->unit == CSSPrimitiveValue::CSS_IDENT && equalIgnoringCase(a, "at")) {
-        a = args->next();
-        if (!a)
+    RefPtr<CSSPrimitiveValue> centerX;
+    RefPtr<CSSPrimitiveValue> centerY;
+    if (argument->unit == CSSPrimitiveValue::CSS_IDENT && equalLettersIgnoringASCIICase(*argument, "at")) {
+        argument = args->next();
+        if (!argument)
             return false;
 
-        parseFillPosition(args, centerX, centerY);
-        ASSERT(centerX->isPrimitiveValue());
-        ASSERT(centerY->isPrimitiveValue());
+        parseFillPosition(*args, centerX, centerY);
         if (!(centerX && centerY))
             return false;
 
-        a = args->current();
-        if (!a)
+        argument = args->current();
+        if (!argument)
             return false;
-        result->setFirstX(static_cast<CSSPrimitiveValue*>(centerX.get()));
-        result->setFirstY(static_cast<CSSPrimitiveValue*>(centerY.get()));
+
+        result->setFirstX(centerX);
+        result->setFirstY(centerY);
         // Right now, CSS radial gradients have the same start and end centers.
-        result->setSecondX(static_cast<CSSPrimitiveValue*>(centerX.get()));
-        result->setSecondY(static_cast<CSSPrimitiveValue*>(centerY.get()));
+        result->setSecondX(centerX);
+        result->setSecondY(centerY);
     }
 
     if (shapeValue || sizeValue || horizontalSize || centerX || centerY)
         expectComma = true;
 
-    if (!parseGradientColorStops(args, result.get(), expectComma))
+    if (!parseGradientColorStops(*args, *result, expectComma))
         return false;
 
     gradient = result.release();
     return true;
 }
 
-bool CSSParser::parseGradientColorStops(CSSParserValueList* valueList, CSSGradientValue* gradient, bool expectComma)
+bool CSSParser::parseGradientColorStops(CSSParserValueList& valueList, CSSGradientValue& gradient, bool expectComma)
 {
-    CSSParserValue* a = valueList->current();
+    CSSParserValue* value = valueList.current();
+    bool previousStopWasMidpoint = true;
 
     // Now look for color stops.
-    while (a) {
+    while (value) {
         // Look for the comma before the next stop.
         if (expectComma) {
-            if (!isComma(a))
+            if (!isComma(value))
                 return false;
 
-            a = valueList->next();
-            if (!a)
+            value = valueList.next();
+            if (!value)
                 return false;
         }
 
         // <color-stop> = <color> [ <percentage> | <length> ]?
         CSSGradientColorStop stop;
-        stop.m_color = parseGradientColorOrKeyword(this, a);
-        if (!stop.m_color)
-            return false;
+        stop.m_color = parseGradientColorOrKeyword(*this, *value);
+        if (!stop.m_color) {
+            if (previousStopWasMidpoint) // 2 midpoints in a row is not allowed. This also catches starting with a midpoint.
+                return false;
 
-        a = valueList->next();
-        if (a) {
-            if (validUnit(a, FLength | FPercent)) {
-                stop.m_position = createPrimitiveNumericValue(a);
-                a = valueList->next();
-            }
+            stop.isMidpoint = true;
+        } else
+            value = valueList.next();
+
+        previousStopWasMidpoint = stop.isMidpoint;
+
+        if (value) {
+            ValueWithCalculation valueWithCalculation(*value);
+            if (validateUnit(valueWithCalculation, FLength | FPercent)) {
+                stop.m_position = createPrimitiveNumericValue(valueWithCalculation);
+                value = valueList.next();
+            } else if (stop.isMidpoint)
+                return false;
         }
 
-        gradient->addStop(stop);
+        gradient.addStop(stop);
         expectComma = true;
     }
 
+    // We can't end on a midpoint.
+    if (previousStopWasMidpoint)
+        return false;
+
     // Must have 2 or more stops to be valid.
-    return gradient->stopCount() >= 2;
+    return gradient.stopCount() >= 2;
 }
 
-bool CSSParser::isGeneratedImageValue(CSSParserValue* val) const
+bool CSSParser::isGeneratedImageValue(CSSParserValue& value) const
 {
-    if (val->unit != CSSParserValue::Function)
+    if (value.unit != CSSParserValue::Function)
         return false;
 
-    return equalIgnoringCase(val->function->name, "-webkit-gradient(")
-        || equalIgnoringCase(val->function->name, "-webkit-linear-gradient(")
-        || equalIgnoringCase(val->function->name, "linear-gradient(")
-        || equalIgnoringCase(val->function->name, "-webkit-repeating-linear-gradient(")
-        || equalIgnoringCase(val->function->name, "repeating-linear-gradient(")
-        || equalIgnoringCase(val->function->name, "-webkit-radial-gradient(")
-        || equalIgnoringCase(val->function->name, "radial-gradient(")
-        || equalIgnoringCase(val->function->name, "-webkit-repeating-radial-gradient(")
-        || equalIgnoringCase(val->function->name, "repeating-radial-gradient(")
-        || equalIgnoringCase(val->function->name, "-webkit-canvas(")
-        || equalIgnoringCase(val->function->name, "-webkit-cross-fade(");
+    return equalLettersIgnoringASCIICase(value.function->name, "-webkit-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-linear-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "linear-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-repeating-linear-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "repeating-linear-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-radial-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "radial-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-repeating-radial-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "repeating-radial-gradient(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-canvas(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-cross-fade(")
+        || equalLettersIgnoringASCIICase(value.function->name, "filter(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-filter(")
+        || equalLettersIgnoringASCIICase(value.function->name, "-webkit-named-image(");
 }
 
-bool CSSParser::parseGeneratedImage(CSSParserValueList* valueList, RefPtr<CSSValue>& value)
+bool CSSParser::parseGeneratedImage(CSSParserValueList& valueList, RefPtr<CSSValue>& value)
 {
-    CSSParserValue* val = valueList->current();
+    CSSParserValue& parserValue = *valueList.current();
 
-    if (val->unit != CSSParserValue::Function)
+    if (parserValue.unit != CSSParserValue::Function)
         return false;
 
-    if (equalIgnoringCase(val->function->name, "-webkit-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-gradient("))
         return parseDeprecatedGradient(valueList, value);
 
-    if (equalIgnoringCase(val->function->name, "-webkit-linear-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-linear-gradient("))
         return parseDeprecatedLinearGradient(valueList, value, NonRepeating);
 
-    if (equalIgnoringCase(val->function->name, "linear-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "linear-gradient("))
         return parseLinearGradient(valueList, value, NonRepeating);
 
-    if (equalIgnoringCase(val->function->name, "-webkit-repeating-linear-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-repeating-linear-gradient("))
         return parseDeprecatedLinearGradient(valueList, value, Repeating);
 
-    if (equalIgnoringCase(val->function->name, "repeating-linear-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "repeating-linear-gradient("))
         return parseLinearGradient(valueList, value, Repeating);
 
-    if (equalIgnoringCase(val->function->name, "-webkit-radial-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-radial-gradient("))
         return parseDeprecatedRadialGradient(valueList, value, NonRepeating);
 
-    if (equalIgnoringCase(val->function->name, "radial-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "radial-gradient("))
         return parseRadialGradient(valueList, value, NonRepeating);
 
-    if (equalIgnoringCase(val->function->name, "-webkit-repeating-radial-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-repeating-radial-gradient("))
         return parseDeprecatedRadialGradient(valueList, value, Repeating);
 
-    if (equalIgnoringCase(val->function->name, "repeating-radial-gradient("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "repeating-radial-gradient("))
         return parseRadialGradient(valueList, value, Repeating);
 
-    if (equalIgnoringCase(val->function->name, "-webkit-canvas("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-canvas("))
         return parseCanvas(valueList, value);
 
-    if (equalIgnoringCase(val->function->name, "-webkit-cross-fade("))
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-cross-fade("))
         return parseCrossfade(valueList, value);
 
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "filter(") || equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-filter("))
+        return parseFilterImage(valueList, value);
+
+    if (equalLettersIgnoringASCIICase(parserValue.function->name, "-webkit-named-image("))
+        return parseNamedImage(valueList, value);
+
     return false;
 }
 
-bool CSSParser::parseCrossfade(CSSParserValueList* valueList, RefPtr<CSSValue>& crossfade)
+bool CSSParser::parseFilterImage(CSSParserValueList& valueList, RefPtr<CSSValue>& filter)
+{
+    RefPtr<CSSFilterImageValue> result;
+
+    // Walk the arguments.
+    CSSParserValueList* args = valueList.current()->function->args.get();
+    if (!args)
+        return false;
+    CSSParserValue* value = args->current();
+    RefPtr<CSSValue> imageValue;
+    RefPtr<CSSValue> filterValue;
+
+    if (!value)
+        return false;
+
+    // The first argument is the image. It is a fill image.
+    if (!parseFillImage(*args, imageValue)) {
+        if (value->unit == CSSPrimitiveValue::CSS_STRING)
+            imageValue = CSSImageValue::create(completeURL(value->string));
+        else
+            return false;
+    }
+
+    value = args->next();
+
+    // Skip a comma
+    if (!isComma(value))
+        return false;
+    value = args->next();
+
+    if (!value || !parseFilter(*args, filterValue))
+        return false;
+    value = args->next();
+
+    result = CSSFilterImageValue::create(imageValue.releaseNonNull(), filterValue.releaseNonNull());
+
+    filter = result;
+
+    return true;
+}
+
+bool CSSParser::parseCrossfade(CSSParserValueList& valueList, RefPtr<CSSValue>& crossfade)
 {
     RefPtr<CSSCrossfadeValue> result;
 
     // Walk the arguments.
-    CSSParserValueList* args = valueList->current()->function->args.get();
+    CSSParserValueList* args = valueList.current()->function->args.get();
     if (!args || args->size() != 5)
         return false;
-    CSSParserValue* a = args->current();
+    CSSParserValue* argument = args->current();
     RefPtr<CSSValue> fromImageValue;
     RefPtr<CSSValue> toImageValue;
 
     // The first argument is the "from" image. It is a fill image.
-    if (!a || !parseFillImage(args, fromImageValue))
+    if (!argument || !parseFillImage(*args, fromImageValue))
         return false;
-    a = args->next();
+    argument = args->next();
 
     // Skip a comma
-    if (!isComma(a))
+    if (!isComma(argument))
         return false;
-    a = args->next();
+    argument = args->next();
 
     // The second argument is the "to" image. It is a fill image.
-    if (!a || !parseFillImage(args, toImageValue))
+    if (!argument || !parseFillImage(*args, toImageValue))
         return false;
-    a = args->next();
+    argument = args->next();
 
     // Skip a comma
-    if (!isComma(a))
+    if (!isComma(argument))
         return false;
-    a = args->next();
+    argument = args->next();
 
     // The third argument is the crossfade value. It is a percentage or a fractional number.
     RefPtr<CSSPrimitiveValue> percentage;
-    if (!a)
+    if (!argument)
         return false;
     
-    if (a->unit == CSSPrimitiveValue::CSS_PERCENTAGE)
-        percentage = cssValuePool().createValue(clampTo<double>(a->fValue / 100, 0, 1), CSSPrimitiveValue::CSS_NUMBER);
-    else if (a->unit == CSSPrimitiveValue::CSS_NUMBER)
-        percentage = cssValuePool().createValue(clampTo<double>(a->fValue, 0, 1), CSSPrimitiveValue::CSS_NUMBER);
+    if (argument->unit == CSSPrimitiveValue::CSS_PERCENTAGE)
+        percentage = CSSValuePool::singleton().createValue(clampTo<double>(argument->fValue / 100, 0, 1), CSSPrimitiveValue::CSS_NUMBER);
+    else if (argument->unit == CSSPrimitiveValue::CSS_NUMBER)
+        percentage = CSSValuePool::singleton().createValue(clampTo<double>(argument->fValue, 0, 1), CSSPrimitiveValue::CSS_NUMBER);
     else
         return false;
 
@@ -7987,10 +9487,10 @@ bool CSSParser::parseCrossfade(CSSParserValueList* valueList, RefPtr<CSSValue>&
     return true;
 }
 
-bool CSSParser::parseCanvas(CSSParserValueList* valueList, RefPtr<CSSValue>& canvas)
+bool CSSParser::parseCanvas(CSSParserValueList& valueList, RefPtr<CSSValue>& canvas)
 {
     // Walk the arguments.
-    CSSParserValueList* args = valueList->current()->function->args.get();
+    CSSParserValueList* args = valueList.current()->function->args.get();
     if (!args || args->size() != 1)
         return false;
 
@@ -8003,8 +9503,23 @@ bool CSSParser::parseCanvas(CSSParserValueList* valueList, RefPtr<CSSValue>& can
     return true;
 }
 
+bool CSSParser::parseNamedImage(CSSParserValueList& valueList, RefPtr<CSSValue>& namedImage)
+{
+    CSSParserValueList* args = valueList.current()->function->args.get();
+    if (!args || args->size() != 1)
+        return false;
+
+    // The only argument is the image name.
+    CSSParserValue* value = args->current();
+    if (!value || value->unit != CSSPrimitiveValue::CSS_IDENT)
+        return false;
+
+    namedImage = CSSNamedImageValue::create(value->string);
+    return true;
+}
+
 #if ENABLE(CSS_IMAGE_RESOLUTION)
-PassRefPtr<CSSValue> CSSParser::parseImageResolution()
+RefPtr<CSSValue> CSSParser::parseImageResolution()
 {
     RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     bool haveResolution = false;
@@ -8013,53 +9528,54 @@ PassRefPtr<CSSValue> CSSParser::parseImageResolution()
 
     CSSParserValue* value = m_valueList->current();
     while (value) {
+        ValueWithCalculation valueWithCalculation(*value);
         if (!haveFromImage && value->id == CSSValueFromImage) {
-            list->append(cssValuePool().createIdentifierValue(value->id));
+            list->append(CSSValuePool::singleton().createIdentifierValue(value->id));
             haveFromImage = true;
         } else if (!haveSnap && value->id == CSSValueSnap) {
-            list->append(cssValuePool().createIdentifierValue(value->id));
+            list->append(CSSValuePool::singleton().createIdentifierValue(value->id));
             haveSnap = true;
-        } else if (!haveResolution && validUnit(value, FResolution | FNonNeg) && value->fValue > 0) {
-            list->append(createPrimitiveNumericValue(value));
+        } else if (!haveResolution && validateUnit(valueWithCalculation, FResolution | FNonNeg) && value->fValue > 0) {
+            list->append(createPrimitiveNumericValue(valueWithCalculation));
             haveResolution = true;
         } else
-            return 0;
+            return nullptr;
         value = m_valueList->next();
     }
     if (!list->length())
-        return 0;
+        return nullptr;
     if (!haveFromImage && !haveResolution)
-        return 0;
-    return list.release();
+        return nullptr;
+    return list;
 }
 #endif
 
 #if ENABLE(CSS_IMAGE_SET)
-PassRefPtr<CSSValue> CSSParser::parseImageSet()
+RefPtr<CSSValue> CSSParser::parseImageSet()
 {
-    CSSParserValue* value = m_valueList->current();
-    ASSERT(value->unit == CSSParserValue::Function);
+    CSSParserValue& value = *m_valueList->current();
+    ASSERT(value.unit == CSSParserValue::Function);
 
-    CSSParserValueList* functionArgs = value->function->args.get();
+    CSSParserValueList* functionArgs = value.function->args.get();
     if (!functionArgs || !functionArgs->size() || !functionArgs->current())
-        return 0;
+        return nullptr;
 
     RefPtr<CSSImageSetValue> imageSet = CSSImageSetValue::create();
     CSSParserValue* arg = functionArgs->current();
     while (arg) {
         if (arg->unit != CSSPrimitiveValue::CSS_URI)
-            return 0;
+            return nullptr;
 
         imageSet->append(CSSImageValue::create(completeURL(arg->string)));
         arg = functionArgs->next();
         if (!arg || arg->unit != CSSPrimitiveValue::CSS_DIMENSION)
-            return 0;
+            return nullptr;
 
         double imageScaleFactor = 0;
         const String& string = arg->string;
         unsigned length = string.length();
         if (!length)
-            return 0;
+            return nullptr;
         if (string.is8Bit()) {
             const LChar* start = string.characters8();
             parseDouble(start, start + length, 'x', imageScaleFactor);
@@ -8068,8 +9584,8 @@ PassRefPtr<CSSValue> CSSParser::parseImageSet()
             parseDouble(start, start + length, 'x', imageScaleFactor);
         }
         if (imageScaleFactor <= 0)
-            return 0;
-        imageSet->append(cssValuePool().createValue(imageScaleFactor, CSSPrimitiveValue::CSS_NUMBER));
+            return nullptr;
+        imageSet->append(CSSValuePool::singleton().createValue(imageScaleFactor, CSSPrimitiveValue::CSS_NUMBER));
 
         // If there are no more arguments, we're done.
         arg = functionArgs->next();
@@ -8078,13 +9594,13 @@ PassRefPtr<CSSValue> CSSParser::parseImageSet()
 
         // If there are more arguments, they should be after a comma.
         if (!isComma(arg))
-            return 0;
+            return nullptr;
 
         // Skip the comma and move on to the next argument.
         arg = functionArgs->next();
     }
 
-    return imageSet.release();
+    return imageSet;
 }
 #endif
 
@@ -8347,40 +9863,40 @@ private:
     CSSParser::Units m_unit;
 };
 
-PassRefPtr<CSSValueList> CSSParser::parseTransform()
+RefPtr<CSSValueList> CSSParser::parseTransform()
 {
     if (!m_valueList)
-        return 0;
+        return nullptr;
 
     RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
-        RefPtr<CSSValue> parsedTransformValue = parseTransformValue(value);
+        RefPtr<CSSValue> parsedTransformValue = parseTransformValue(*value);
         if (!parsedTransformValue)
-            return 0;
+            return nullptr;
 
-        list->append(parsedTransformValue.release());
+        list->append(parsedTransformValue.releaseNonNull());
     }
 
-    return list.release();
+    return list;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseTransformValue(CSSParserValue *value)
+RefPtr<CSSValue> CSSParser::parseTransformValue(CSSParserValue& value)
 {
-    if (value->unit != CSSParserValue::Function || !value->function)
-        return 0;
+    if (value.unit != CSSParserValue::Function || !value.function)
+        return nullptr;
 
     // Every primitive requires at least one argument.
-    CSSParserValueList* args = value->function->args.get();
+    CSSParserValueList* args = value.function->args.get();
     if (!args)
-        return 0;
+        return nullptr;
 
     // See if the specified primitive is one we understand.
-    TransformOperationInfo info(value->function->name);
+    TransformOperationInfo info(value.function->name);
     if (info.unknown())
-        return 0;
+        return nullptr;
 
     if (!info.hasCorrectArgCount(args->size()))
-        return 0;
+        return nullptr;
 
     // The transform is a list of functional primitives that specify transform operations.
     // We collect a list of WebKitCSSTransformValues, where each value specifies a single operation.
@@ -8389,41 +9905,42 @@ PassRefPtr<CSSValue> CSSParser::parseTransformValue(CSSParserValue *value)
     RefPtr<WebKitCSSTransformValue> transformValue = WebKitCSSTransformValue::create(info.type());
 
     // Snag our values.
-    CSSParserValue* a = args->current();
+    CSSParserValue* argument = args->current();
     unsigned argNumber = 0;
-    while (a) {
+    while (argument) {
+        ValueWithCalculation argumentWithCalculation(*argument);
         CSSParser::Units unit = info.unit();
 
         if (info.type() == WebKitCSSTransformValue::Rotate3DTransformOperation && argNumber == 3) {
             // 4th param of rotate3d() is an angle rather than a bare number, validate it as such
-            if (!validUnit(a, FAngle, CSSStrictMode))
-                return 0;
+            if (!validateUnit(argumentWithCalculation, FAngle, CSSStrictMode))
+                return nullptr;
         } else if (info.type() == WebKitCSSTransformValue::Translate3DTransformOperation && argNumber == 2) {
             // 3rd param of translate3d() cannot be a percentage
-            if (!validUnit(a, FLength, CSSStrictMode))
-                return 0;
+            if (!validateUnit(argumentWithCalculation, FLength, CSSStrictMode))
+                return nullptr;
         } else if (info.type() == WebKitCSSTransformValue::TranslateZTransformOperation && !argNumber) {
             // 1st param of translateZ() cannot be a percentage
-            if (!validUnit(a, FLength, CSSStrictMode))
-                return 0;
+            if (!validateUnit(argumentWithCalculation, FLength, CSSStrictMode))
+                return nullptr;
         } else if (info.type() == WebKitCSSTransformValue::PerspectiveTransformOperation && !argNumber) {
             // 1st param of perspective() must be a non-negative number (deprecated) or length.
-            if (!validUnit(a, FNumber | FLength | FNonNeg, CSSStrictMode))
-                return 0;
-        } else if (!validUnit(a, unit, CSSStrictMode))
-            return 0;
+            if (!validateUnit(argumentWithCalculation, FNumber | FLength | FNonNeg, CSSStrictMode))
+                return nullptr;
+        } else if (!validateUnit(argumentWithCalculation, unit, CSSStrictMode))
+            return nullptr;
 
         // Add the value to the current transform operation.
-        transformValue->append(createPrimitiveNumericValue(a));
+        transformValue->append(createPrimitiveNumericValue(argumentWithCalculation));
 
-        a = args->next();
-        if (!a)
+        argument = args->next();
+        if (!argument)
             break;
-        if (a->unit != CSSParserValue::Operator || a->iValue != ',')
-            return 0;
-        a = args->next();
+        if (argument->unit != CSSParserValue::Operator || argument->iValue != ',')
+            return nullptr;
+        argument = args->next();
 
-        argNumber++;
+        ++argNumber;
     }
 
     return transformValue.release();
@@ -8442,626 +9959,35 @@ bool CSSParser::isCompositeOperator(CSSValueID valueID)
     return valueID >= CSSValueClear && valueID <= CSSValueXor;
 }
 
-#if ENABLE(CSS_FILTERS)
-
 static void filterInfoForName(const CSSParserString& name, WebKitCSSFilterValue::FilterOperationType& filterType, unsigned& maximumArgumentCount)
 {
-    if (equalIgnoringCase(name, "grayscale("))
+    if (equalLettersIgnoringASCIICase(name, "grayscale("))
         filterType = WebKitCSSFilterValue::GrayscaleFilterOperation;
-    else if (equalIgnoringCase(name, "sepia("))
+    else if (equalLettersIgnoringASCIICase(name, "sepia("))
         filterType = WebKitCSSFilterValue::SepiaFilterOperation;
-    else if (equalIgnoringCase(name, "saturate("))
+    else if (equalLettersIgnoringASCIICase(name, "saturate("))
         filterType = WebKitCSSFilterValue::SaturateFilterOperation;
-    else if (equalIgnoringCase(name, "hue-rotate("))
+    else if (equalLettersIgnoringASCIICase(name, "hue-rotate("))
         filterType = WebKitCSSFilterValue::HueRotateFilterOperation;
-    else if (equalIgnoringCase(name, "invert("))
+    else if (equalLettersIgnoringASCIICase(name, "invert("))
         filterType = WebKitCSSFilterValue::InvertFilterOperation;
-    else if (equalIgnoringCase(name, "opacity("))
+    else if (equalLettersIgnoringASCIICase(name, "opacity("))
         filterType = WebKitCSSFilterValue::OpacityFilterOperation;
-    else if (equalIgnoringCase(name, "brightness("))
+    else if (equalLettersIgnoringASCIICase(name, "brightness("))
         filterType = WebKitCSSFilterValue::BrightnessFilterOperation;
-    else if (equalIgnoringCase(name, "contrast("))
+    else if (equalLettersIgnoringASCIICase(name, "contrast("))
         filterType = WebKitCSSFilterValue::ContrastFilterOperation;
-    else if (equalIgnoringCase(name, "blur("))
+    else if (equalLettersIgnoringASCIICase(name, "blur("))
         filterType = WebKitCSSFilterValue::BlurFilterOperation;
-    else if (equalIgnoringCase(name, "drop-shadow(")) {
+    else if (equalLettersIgnoringASCIICase(name, "drop-shadow(")) {
         filterType = WebKitCSSFilterValue::DropShadowFilterOperation;
         maximumArgumentCount = 4;  // x-offset, y-offset, blur-radius, color -- spread and inset style not allowed.
     }
-#if ENABLE(CSS_SHADERS)
-    else if (equalIgnoringCase(name, "custom("))
-        filterType = WebKitCSSFilterValue::CustomFilterOperation;
-#endif
-}
-
-#if ENABLE(CSS_SHADERS)
-static bool acceptCommaOperator(CSSParserValueList* argsList)
-{
-    if (CSSParserValue* arg = argsList->current()) {
-        if (!isComma(arg))
-            return false;
-        argsList->next();
-    }
-    return true;
-}
-
-PassRefPtr<WebKitCSSArrayFunctionValue> CSSParser::parseCustomFilterArrayFunction(CSSParserValue* value)
-{
-    ASSERT(value->unit == CSSParserValue::Function && value->function);
-
-    if (!equalIgnoringCase(value->function->name, "array("))
-        return 0;
-
-    CSSParserValueList* arrayArgsParserValueList = value->function->args.get();
-    if (!arrayArgsParserValueList || !arrayArgsParserValueList->size())
-        return 0;
-
-    // array() values are comma separated.
-    RefPtr<WebKitCSSArrayFunctionValue> arrayFunction = WebKitCSSArrayFunctionValue::create();
-    while (true) {
-        // We parse pairs <Value, Comma> at each step.
-        CSSParserValue* currentParserValue = arrayArgsParserValueList->current();
-        if (!currentParserValue || !validUnit(currentParserValue, FNumber, CSSStrictMode))
-            return 0;
-
-        RefPtr<CSSValue> arrayValue = cssValuePool().createValue(currentParserValue->fValue, CSSPrimitiveValue::CSS_NUMBER);
-        arrayFunction->append(arrayValue.release());
-
-        CSSParserValue* nextParserValue = arrayArgsParserValueList->next();
-        if (!nextParserValue)
-            break;
-
-        if (!isComma(nextParserValue))
-            return 0;
-
-        arrayArgsParserValueList->next();
-    }
-
-    return arrayFunction;
-}
-
-PassRefPtr<WebKitCSSMatFunctionValue> CSSParser::parseMatValue(CSSParserValue* value)
-{
-    if (value->unit != CSSParserValue::Function || !value->function)
-        return 0;
-
-    unsigned numberOfValues = 0;
-    if (equalIgnoringCase(value->function->name, "mat2("))
-        numberOfValues = 4;
-    else if (equalIgnoringCase(value->function->name, "mat3("))
-        numberOfValues = 9;
-    else if (equalIgnoringCase(value->function->name, "mat4("))
-        numberOfValues = 16;
-    else
-        return 0;
-
-    CSSParserValueList* args = value->function->args.get();
-    if (!args || args->size() != (numberOfValues * 2 - 1))
-        return 0;
-
-    RefPtr<WebKitCSSMatFunctionValue> matValueList = WebKitCSSMatFunctionValue::create();
-    CSSParserValue* arg = args->current();
-    while (arg) {
-        if (!validUnit(arg, FNumber, CSSStrictMode))
-            return 0;
-        matValueList->append(cssValuePool().createValue(arg->fValue, CSSPrimitiveValue::CSS_NUMBER));
-        arg = args->next();
-
-        if (!arg)
-            break;
-
-        if (!isComma(arg))
-            return 0;
-
-        arg = args->next();
-    }
-
-    if (!matValueList || matValueList->length() != numberOfValues)
-        return 0;
-
-    return matValueList.release();
-}
-
-PassRefPtr<WebKitCSSMixFunctionValue> CSSParser::parseMixFunction(CSSParserValue* value)
-{
-    ASSERT(value->unit == CSSParserValue::Function && value->function);
-
-    if (!equalIgnoringCase(value->function->name, "mix("))
-        return 0;
-
-    CSSParserValueList* argsList = value->function->args.get();
-    if (!argsList)
-        return 0;
-
-    unsigned numArgs = argsList->size();
-    if (numArgs < 1 || numArgs > 3)
-        return 0;
-    
-    RefPtr<WebKitCSSMixFunctionValue> mixFunction = WebKitCSSMixFunctionValue::create();
-
-    bool hasBlendMode = false;
-    bool hasAlphaCompositing = false;
-    CSSParserValue* arg;
-    while ((arg = argsList->current())) {
-        RefPtr<CSSValue> value;
-
-        unsigned argNumber = argsList->currentIndex();
-        if (!argNumber) {
-            if (arg->unit == CSSPrimitiveValue::CSS_URI) {
-                KURL shaderURL = completeURL(arg->string);
-                value = WebKitCSSShaderValue::create(shaderURL.string());
-            }
-        } else if (argNumber == 1 || argNumber == 2) {
-            if (!hasBlendMode && isBlendMode(arg->id)) {
-                hasBlendMode = true;
-                value = cssValuePool().createIdentifierValue(arg->id);
-            } else if (!hasAlphaCompositing && isCompositeOperator(arg->id)) {
-                hasAlphaCompositing = true;
-                value = cssValuePool().createIdentifierValue(arg->id);
-            }
-        }
-
-        if (!value)
-            return 0;
-
-        mixFunction->append(value.release());
-
-        arg = argsList->next();
-    }
-
-    return mixFunction;
-}
-
-PassRefPtr<CSSValueList> CSSParser::parseCustomFilterParameters(CSSParserValueList* argsList)
-{
-    //
-    // params:      [<param-def>[,<param-def>*]]
-    // param-def:   <param-name>wsp<param-value>
-    // param-name:  <ident>
-    // param-value: true|false[wsp+true|false]{0-3} |
-    //              <number>[wsp+<number>]{0-3} |
-    //              <array> |
-    //              <transform> |
-    //              <texture(<uri>)>
-    // array: 'array('<number>[wsp<number>]*')'
-    // css-3d-transform: <transform-function>;[<transform-function>]*
-    // transform:   <css-3d-transform> | <mat>
-    // mat:         'mat2('<number>(,<number>){3}')' | 
-    //              'mat3('<number>(,<number>){8}')' | 
-    //              'mat4('<number>(,<number>){15}')' )
-    //
-
-    RefPtr<CSSValueList> paramList = CSSValueList::createCommaSeparated();
-
-    while (CSSParserValue* arg = argsList->current()) {
-        if (arg->unit != CSSPrimitiveValue::CSS_IDENT)
-            return 0;
-
-        RefPtr<CSSValueList> parameter = CSSValueList::createSpaceSeparated();
-        parameter->append(createPrimitiveStringValue(arg));
-
-        arg = argsList->next();
-        if (!arg)
-            return 0;
-
-        RefPtr<CSSValue> parameterValue;
-
-        if (arg->unit == CSSParserValue::Function && arg->function) {
-            // FIXME: Implement parsing for the other parameter types.
-            // textures: https://bugs.webkit.org/show_bug.cgi?id=71442
-            if (equalIgnoringCase(arg->function->name, "array(")) {
-                parameterValue = parseCustomFilterArrayFunction(arg);
-                // This parsing step only consumes function arguments,
-                // argsList is therefore moved forward explicitely.
-                argsList->next();
-            } else {
-                // Parse mat2, mat3 and mat4 functions.
-                parameterValue = parseMatValue(arg);
-                if (!parameterValue && arg)
-                    parameterValue = parseCustomFilterTransform(argsList);
-                else if (parameterValue)
-                    argsList->next();
-            }
-        } else if (validUnit(arg, FNumber, CSSStrictMode)) {
-            RefPtr<CSSValueList> paramValueList = CSSValueList::createSpaceSeparated();
-            while (arg) {
-                // If we hit a comma, it means that we finished this parameter's values.
-                if (isComma(arg))
-                    break;
-                if (!validUnit(arg, FNumber, CSSStrictMode))
-                    return 0;
-                paramValueList->append(cssValuePool().createValue(arg->fValue, CSSPrimitiveValue::CSS_NUMBER));
-                arg = argsList->next();
-            }
-            if (!paramValueList->length() || paramValueList->length() > 4)
-                return 0;
-            parameterValue = paramValueList.release();
-        }
-        if (!parameterValue && arg) {
-            // All parameter values need to be CSSValueLists.
-            RefPtr<CSSValueList> paramValueList = CSSValueList::createSpaceSeparated();
-            RefPtr<CSSPrimitiveValue> colorValue = parseColor(arg);
-            if (!colorValue)
-                return 0;
-            paramValueList->append(colorValue.release());
-            parameterValue = paramValueList.release();
-            arg = argsList->next();
-        }
-
-        if (!parameterValue || !acceptCommaOperator(argsList))
-            return 0;
-
-        parameter->append(parameterValue.release());
-        paramList->append(parameter.release());
-    }
-
-    return paramList;   
 }
 
-PassRefPtr<WebKitCSSFilterValue> CSSParser::parseCustomFilterFunctionWithAtRuleReferenceSyntax(CSSParserValue* value)
-{
-    //
-    // Custom filter function "at-rule reference" syntax:
-    //
-    // custom(<filter-name>wsp[,wsp<params>])
-    //
-    // filter-name: <filter-name>
-    // params: See the comment in CSSParser::parseCustomFilterParameters.
-    //
-
-    ASSERT(value->function);
-
-    CSSParserValueList* argsList = value->function->args.get();
-    if (!argsList || !argsList->size())
-        return 0;
-
-    // 1. Parse the filter name.
-    CSSParserValue* arg = argsList->current();
-    if (arg->unit != CSSPrimitiveValue::CSS_IDENT)
-        return 0;
-
-    RefPtr<WebKitCSSFilterValue> filterValue = WebKitCSSFilterValue::create(WebKitCSSFilterValue::CustomFilterOperation);
-
-    RefPtr<CSSValue> filterName = createPrimitiveStringValue(arg);
-    filterValue->append(filterName);
-    argsList->next();
-
-    if (!acceptCommaOperator(argsList))
-        return 0;
-
-    // 2. Parse the parameters.
-    RefPtr<CSSValueList> paramList = parseCustomFilterParameters(argsList);
-    if (!paramList)
-        return 0;
-
-    if (paramList->length())
-        filterValue->append(paramList.release());
-
-    return filterValue;
-}
-
-// FIXME: The custom filters "inline" syntax is deprecated. We will remove it eventually.
-PassRefPtr<WebKitCSSFilterValue> CSSParser::parseCustomFilterFunctionWithInlineSyntax(CSSParserValue* value)
-{
-    //
-    // Custom filter function "inline" syntax:
-    //
-    // custom(<vertex-shader>[wsp<fragment-shader>][,<vertex-mesh>][,<params>])
-    //
-    // vertexShader:    <uri> | none
-    // fragmentShader:  <uri> | none | mix(<uri> [ <blend-mode> || <alpha-compositing> ]?)
-    //
-    // blend-mode: normal | multiply | screen | overlay | darken | lighten | color-dodge |
-    //             color-burn | hard-light | soft-light | difference | exclusion | hue |
-    //             saturation | color | luminosity
-    // alpha-compositing: clear | src | dst | src-over | dst-over | src-in | dst-in |
-    //                    src-out | dst-out | src-atop | dst-atop | xor | plus
-    //
-    // vertexMesh:  +<integer>{1,2}[wsp<box>][wsp'detached']
-    // box: filter-box | border-box | padding-box | content-box
-    //
-    // params: See the comment in CSSParser::parseCustomFilterParameters.
-    //
-
-    ASSERT(value->function);
-
-    CSSParserValueList* argsList = value->function->args.get();
-    if (!argsList)
-        return 0;
-
-    RefPtr<WebKitCSSFilterValue> filterValue = WebKitCSSFilterValue::create(WebKitCSSFilterValue::CustomFilterOperation);
-
-    // 1. Parse the shader URLs: <vertex-shader>[wsp<fragment-shader>]
-    RefPtr<CSSValueList> shadersList = CSSValueList::createSpaceSeparated();
-    bool hadAtLeastOneCustomShader = false;
-    CSSParserValue* arg;
-    while ((arg = argsList->current())) {
-        RefPtr<CSSValue> value;
-        if (arg->id == CSSValueNone)
-            value = cssValuePool().createIdentifierValue(CSSValueNone);
-        else if (arg->unit == CSSPrimitiveValue::CSS_URI) {
-            KURL shaderURL = completeURL(arg->string);
-            value = WebKitCSSShaderValue::create(shaderURL.string());
-            hadAtLeastOneCustomShader = true;
-        } else if (argsList->currentIndex() == 1 && arg->unit == CSSParserValue::Function) {
-            if (!(value = parseMixFunction(arg)))
-                return 0;
-            hadAtLeastOneCustomShader = true;
-        }
-
-        if (!value)
-            break;
-        shadersList->append(value.release());
-        argsList->next();
-    }
-
-    if (!shadersList->length() || !hadAtLeastOneCustomShader || shadersList->length() > 2 || !acceptCommaOperator(argsList))
-        return 0;
-        
-    filterValue->append(shadersList.release());
-    
-    // 2. Parse the mesh size <vertex-mesh>
-    RefPtr<CSSValueList> meshSizeList = CSSValueList::createSpaceSeparated();
-    
-    while ((arg = argsList->current())) {
-        if (!validUnit(arg, FInteger | FNonNeg, CSSStrictMode))
-            break;
-        int integerValue = clampToInteger(arg->fValue);
-        // According to the specification we can only accept positive non-zero values.
-        if (integerValue < 1)
-            return 0;
-        meshSizeList->append(cssValuePool().createValue(integerValue, CSSPrimitiveValue::CSS_NUMBER));
-        argsList->next();
-    }
-    
-    if (meshSizeList->length() > 2)
-        return 0;
-    
-    // FIXME: For legacy content, we accept the mesh box types. We don't do anything else with them.
-    // Eventually, we'll remove them completely.
-    // https://bugs.webkit.org/show_bug.cgi?id=103778
-    if ((arg = argsList->current()) && (arg->id == CSSValueBorderBox || arg->id == CSSValuePaddingBox
-        || arg->id == CSSValueContentBox || arg->id == CSSValueFilterBox))
-        argsList->next();
-    
-    if ((arg = argsList->current()) && arg->id == CSSValueDetached) {
-        meshSizeList->append(cssValuePool().createIdentifierValue(arg->id));
-        argsList->next();
-    }
-    
-    if (meshSizeList->length()) {
-        if (!acceptCommaOperator(argsList))
-            return 0;
-        filterValue->append(meshSizeList.release());
-    }
-    
-    // 3. Parse the parameters.
-    RefPtr<CSSValueList> paramList = parseCustomFilterParameters(argsList);
-    if (!paramList)
-        return 0;
-
-    if (paramList->length())
-        filterValue->append(paramList.release());
-    
-    return filterValue;
-}
-
-PassRefPtr<WebKitCSSFilterValue> CSSParser::parseCustomFilterFunction(CSSParserValue* value)
-{
-    ASSERT(value->function);
-
-    // Look ahead to determine which syntax the custom function is using.
-    // Both the at-rule reference syntax and the inline syntax require at least one argument.
-    CSSParserValueList* argsList = value->function->args.get();
-    if (!argsList || !argsList->size())
-        return 0;
-
-    // The at-rule reference syntax expects a single ident or an ident followed by a comma. 
-    // e.g. custom(my-filter) or custom(my-filter, ...)
-    // In contrast, when the inline syntax starts with an ident like "none", it expects a uri or a mix function next.
-    // e.g. custom(none url(...)) or custom(none mix(...)
-    bool isAtRuleReferenceSyntax = argsList->valueAt(0)->unit == CSSPrimitiveValue::CSS_IDENT 
-        && (argsList->size() == 1 || isComma(argsList->valueAt(1)));
-    return isAtRuleReferenceSyntax ? parseCustomFilterFunctionWithAtRuleReferenceSyntax(value) : parseCustomFilterFunctionWithInlineSyntax(value);
-}
-
-PassRefPtr<CSSValueList> CSSParser::parseCustomFilterTransform(CSSParserValueList* valueList)
-{
-    if (!valueList)
-        return 0;
-
-    // CSS Shaders' custom() transforms are space separated and comma terminated.
-    RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
-    for (CSSParserValue* value = valueList->current(); value; value = valueList->next()) {
-        if (isComma(value))
-            break;
-
-        RefPtr<CSSValue> parsedTransformValue = parseTransformValue(value);
-        if (!parsedTransformValue)
-            return 0;
-
-        list->append(parsedTransformValue.release());
-    }
-
-    return list.release();
-}
-
-PassRefPtr<WebKitCSSShaderValue> CSSParser::parseFilterRuleSrcUriAndFormat(CSSParserValueList* valueList)
-{
-    CSSParserValue* value = valueList->current();
-    ASSERT(value && value->unit == CSSPrimitiveValue::CSS_URI);
-    RefPtr<WebKitCSSShaderValue> shaderValue = WebKitCSSShaderValue::create(completeURL(value->string));
-
-    value = valueList->next();
-    if (value && value->unit == CSSParserValue::Function && equalIgnoringCase(value->function->name, "format(")) {
-        CSSParserValueList* args = value->function->args.get();
-        if (!args || args->size() != 1)
-            return 0;
-
-        CSSParserValue* arg = args->current();
-        if (arg->unit != CSSPrimitiveValue::CSS_STRING)
-            return 0;
-
-        shaderValue->setFormat(arg->string);
-        valueList->next();
-    }
-
-    return shaderValue.release();
-}
-
-bool CSSParser::parseFilterRuleSrc()
-{
-    RefPtr<CSSValueList> srcList = CSSValueList::createCommaSeparated();
-
-    CSSParserValue* value = m_valueList->current();
-    while (value) {
-        if (value->unit != CSSPrimitiveValue::CSS_URI)
-            return false;
-
-        RefPtr<WebKitCSSShaderValue> shaderValue = parseFilterRuleSrcUriAndFormat(m_valueList.get());
-        if (!shaderValue)
-            return false;
-        srcList->append(shaderValue.release());
-
-        if (!acceptCommaOperator(m_valueList.get()))
-            return false;
-
-        value = m_valueList->current();
-    }
-
-    if (!srcList->length())
-        return false;
-
-    addProperty(CSSPropertySrc, srcList.release(), m_important);
-    return true;
-}
-
-bool CSSParser::parseFilterRuleMix()
-{
-    if (m_valueList->size() > 2)
-        return false;
-
-    RefPtr<CSSValueList> mixList = CSSValueList::createSpaceSeparated();
-
-    bool hasBlendMode = false;
-    bool hasAlphaCompositing = false;
-    CSSParserValue* value = m_valueList->current();
-    while (value) {
-        RefPtr<CSSValue> mixValue;
-        if (!hasBlendMode && isBlendMode(value->id)) {
-            hasBlendMode = true;
-            mixValue = cssValuePool().createIdentifierValue(value->id);
-        } else if (!hasAlphaCompositing && isCompositeOperator(value->id)) {
-            hasAlphaCompositing = true;
-            mixValue = cssValuePool().createIdentifierValue(value->id);
-        }
-
-        if (!mixValue)
-            return false;
-
-        mixList->append(mixValue.release());
-        value = m_valueList->next();
-    }
-
-    addProperty(CSSPropertyMix, mixList.release(), m_important);
-    return true;
-}
-
-bool CSSParser::parseGeometry(CSSPropertyID propId, CSSParserValue* value, bool important)
-{
-    ASSERT(propId == CSSPropertyGeometry);
-
-    // <geometry-shape> = grid(<integer>{1,2} || [ detached | attached ]?)
-    if (value->unit != CSSParserValue::Function || !equalIgnoringCase(value->function->name, "grid("))
-        return false;
-
-    ASSERT(value->function->args);
-
-    // grid() function should have from 1 to 3 arguments.
-    unsigned size = value->function->args->size();
-    if (!size || size > 3)
-        return false;
-
-    CSSParserValueList* gridParserValueList = value->function->args.get();
-    CSSParserValue* gridParserValue = gridParserValueList->current();
-    RefPtr<CSSValueList> geometryList = CSSValueList::createSpaceSeparated();
-
-    bool hasDimensions = false;
-    bool hasConnectivity = false;
-
-    while (gridParserValue) {
-        if (hasDimensions && hasConnectivity) {
-            geometryList.release();
-            return false;
-        }
-
-        if (gridParserValue->id == CSSValueAttached || gridParserValue->id == CSSValueDetached) {
-            hasConnectivity = true;
-            geometryList->append(cssValuePool().createIdentifierValue(gridParserValue->id));
-            gridParserValue = gridParserValueList->next();
-        } else if (!hasDimensions && parseGridDimensions(gridParserValueList, geometryList)) {
-            hasDimensions = true;
-            gridParserValue = gridParserValueList->current();
-        } else {
-            geometryList.release();
-            return false;
-        }
-    }
-
-    addProperty(propId, geometryList.release(), important);
-    return hasDimensions;
-}
-
-bool CSSParser::parseGridDimensions(CSSParserValueList* args, RefPtr<CSSValueList>& gridValueList)
-{
-    ASSERT(args);
-
-    // There must be at least one valid numeric value.
-    CSSParserValue* arg = args->current();
-    if (!arg || !validUnit(arg, FPositiveInteger))
-        return false;
-
-    // A valid numeric value is parsed and then we move on.
-    gridValueList->append(createPrimitiveNumericValue(arg));
-    arg = args->next();
-
-    // If the next argument is not numeric, we are done parsing the grid dimensions.
-    if (!arg || !validUnit(arg, FPositiveInteger))
-        return true;
-
-    // Commit the second numeric value we found.
-    gridValueList->append(createPrimitiveNumericValue(arg));
-    args->next();
-    return true;
-}
-
-bool CSSParser::parseFilterRuleParameters()
-{
-    RefPtr<CSSValueList> paramsList = parseCustomFilterParameters(m_valueList.get());
-    if (!paramsList)
-        return false;
-
-    addProperty(CSSPropertyParameters, paramsList.release(), m_important);
-    return true;
-}
-
-StyleRuleBase* CSSParser::createFilterRule(const CSSParserString& filterName)
-{
-    RefPtr<StyleRuleFilter> rule = StyleRuleFilter::create(filterName);
-    rule->setProperties(createStylePropertySet());
-    clearProperties();
-    StyleRuleFilter* result = rule.get();
-    m_parsedRules.append(rule.release());
-    processAndAddNewRuleToSourceTreeIfNeeded();
-    return result;
-}
-
-#endif // ENABLE(CSS_SHADERS)
-
-PassRefPtr<WebKitCSSFilterValue> CSSParser::parseBuiltinFilterArguments(CSSParserValueList* args, WebKitCSSFilterValue::FilterOperationType filterType)
+RefPtr<WebKitCSSFilterValue> CSSParser::parseBuiltinFilterArguments(CSSParserValueList& args, WebKitCSSFilterValue::FilterOperationType filterType)
 {
     RefPtr<WebKitCSSFilterValue> filterValue = WebKitCSSFilterValue::create(filterType);
-    ASSERT(args);
 
     switch (filterType) {    
     case WebKitCSSFilterValue::GrayscaleFilterOperation:
@@ -9071,77 +9997,77 @@ PassRefPtr<WebKitCSSFilterValue> CSSParser::parseBuiltinFilterArguments(CSSParse
     case WebKitCSSFilterValue::OpacityFilterOperation:
     case WebKitCSSFilterValue::ContrastFilterOperation: {
         // One optional argument, 0-1 or 0%-100%, if missing use 100%.
-        if (args->size() > 1)
-            return 0;
+        if (args.size() > 1)
+            return nullptr;
+
+        if (args.size()) {
+            ValueWithCalculation argumentWithCalculation(*args.current());
+            if (!validateUnit(argumentWithCalculation, FNumber | FPercent | FNonNeg, CSSStrictMode))
+                return nullptr;
+
+            auto primitiveValue = createPrimitiveNumericValue(argumentWithCalculation);
 
-        if (args->size()) {
-            CSSParserValue* value = args->current();
-            if (!validUnit(value, FNumber | FPercent | FNonNeg, CSSStrictMode))
-                return 0;
-                
-            double amount = value->fValue;
-            
             // Saturate and Contrast allow values over 100%.
             if (filterType != WebKitCSSFilterValue::SaturateFilterOperation
                 && filterType != WebKitCSSFilterValue::ContrastFilterOperation) {
-                double maxAllowed = value->unit == CSSPrimitiveValue::CSS_PERCENTAGE ? 100.0 : 1.0;
-                if (amount > maxAllowed)
-                    return 0;
+                double maxAllowed = primitiveValue->primitiveType() == CSSPrimitiveValue::CSS_PERCENTAGE ? 100.0 : 1.0;
+                if (primitiveValue->getDoubleValue() > maxAllowed)
+                    return nullptr;
             }
 
-            filterValue->append(cssValuePool().createValue(amount, static_cast<CSSPrimitiveValue::UnitTypes>(value->unit)));
+            filterValue->append(WTFMove(primitiveValue));
         }
         break;
     }
     case WebKitCSSFilterValue::BrightnessFilterOperation: {
         // One optional argument, if missing use 100%.
-        if (args->size() > 1)
-            return 0;
+        if (args.size() > 1)
+            return nullptr;
 
-        if (args->size()) {
-            CSSParserValue* value = args->current();
-            if (!validUnit(value, FNumber | FPercent, CSSStrictMode))
-                return 0;
+        if (args.size()) {
+            ValueWithCalculation argumentWithCalculation(*args.current());
+            if (!validateUnit(argumentWithCalculation, FNumber | FPercent, CSSStrictMode))
+                return nullptr;
 
-            filterValue->append(cssValuePool().createValue(value->fValue, static_cast<CSSPrimitiveValue::UnitTypes>(value->unit)));
+            filterValue->append(createPrimitiveNumericValue(argumentWithCalculation));
         }
         break;
     }
     case WebKitCSSFilterValue::HueRotateFilterOperation: {
         // hue-rotate() takes one optional angle.
-        if (args->size() > 1)
-            return 0;
+        if (args.size() > 1)
+            return nullptr;
         
-        if (args->size()) {
-            CSSParserValue* argument = args->current();
-            if (!validUnit(argument, FAngle, CSSStrictMode))
-                return 0;
+        if (args.size()) {
+            ValueWithCalculation argumentWithCalculation(*args.current());
+            if (!validateUnit(argumentWithCalculation, FAngle, CSSStrictMode))
+                return nullptr;
         
-            filterValue->append(createPrimitiveNumericValue(argument));
+            filterValue->append(createPrimitiveNumericValue(argumentWithCalculation));
         }
         break;
     }
     case WebKitCSSFilterValue::BlurFilterOperation: {
         // Blur takes a single length. Zero parameters are allowed.
-        if (args->size() > 1)
-            return 0;
+        if (args.size() > 1)
+            return nullptr;
         
-        if (args->size()) {
-            CSSParserValue* argument = args->current();
-            if (!validUnit(argument, FLength | FNonNeg, CSSStrictMode))
-                return 0;
+        if (args.size()) {
+            ValueWithCalculation argumentWithCalculation(*args.current());
+            if (!validateUnit(argumentWithCalculation, FLength | FNonNeg, CSSStrictMode))
+                return nullptr;
 
-            filterValue->append(createPrimitiveNumericValue(argument));
+            filterValue->append(createPrimitiveNumericValue(argumentWithCalculation));
         }
         break;
     }
     case WebKitCSSFilterValue::DropShadowFilterOperation: {
         // drop-shadow() takes a single shadow.
-        RefPtr<CSSValueList> shadowValueList = parseShadow(args, CSSPropertyWebkitFilter);
+        RefPtr<CSSValueList> shadowValueList = parseShadow(args, CSSPropertyFilter);
         if (!shadowValueList || shadowValueList->length() != 1)
-            return 0;
+            return nullptr;
         
-        filterValue->append((shadowValueList.release())->itemWithoutBoundsCheck(0));
+        filterValue->append(*shadowValueList->itemWithoutBoundsCheck(0));
         break;
     }
     default:
@@ -9150,26 +10076,21 @@ PassRefPtr<WebKitCSSFilterValue> CSSParser::parseBuiltinFilterArguments(CSSParse
     return filterValue.release();
 }
 
-PassRefPtr<CSSValueList> CSSParser::parseFilter()
+bool CSSParser::parseFilter(CSSParserValueList& valueList, RefPtr<CSSValue>& result)
 {
-    if (!m_valueList)
-        return 0;
-
     // The filter is a list of functional primitives that specify individual operations.
     RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
-    for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
+    for (auto* value = valueList.current(); value; value = valueList.next()) {
         if (value->unit != CSSPrimitiveValue::CSS_URI && (value->unit != CSSParserValue::Function || !value->function))
-            return 0;
+            return false;
 
         WebKitCSSFilterValue::FilterOperationType filterType = WebKitCSSFilterValue::UnknownFilterOperation;
 
         // See if the specified primitive is one we understand.
         if (value->unit == CSSPrimitiveValue::CSS_URI) {
-#if ENABLE(SVG)
             RefPtr<WebKitCSSFilterValue> referenceFilterValue = WebKitCSSFilterValue::create(WebKitCSSFilterValue::ReferenceFilterOperation);
-            list->append(referenceFilterValue);
-            referenceFilterValue->append(WebKitCSSSVGDocumentValue::create(value->string));
-#endif
+            referenceFilterValue->append(CSSPrimitiveValue::create(value->string, CSSPrimitiveValue::CSS_URI));
+            list->append(referenceFilterValue.releaseNonNull());
         } else {
             const CSSParserString name = value->function->name;
             unsigned maximumArgumentCount = 1;
@@ -9177,45 +10098,33 @@ PassRefPtr<CSSValueList> CSSParser::parseFilter()
             filterInfoForName(name, filterType, maximumArgumentCount);
 
             if (filterType == WebKitCSSFilterValue::UnknownFilterOperation)
-                return 0;
+                return false;
 
-#if ENABLE(CSS_SHADERS)
-            if (filterType == WebKitCSSFilterValue::CustomFilterOperation) {
-                // Make sure parsing fails if custom filters are disabled.
-                if (!m_context.isCSSCustomFilterEnabled)
-                    return 0;
-                
-                RefPtr<WebKitCSSFilterValue> filterValue = parseCustomFilterFunction(value);
-                if (!filterValue)
-                    return 0;
-                list->append(filterValue.release());
-                continue;
-            }
-#endif
             CSSParserValueList* args = value->function->args.get();
             if (!args)
-                return 0;
+                return false;
 
-            RefPtr<WebKitCSSFilterValue> filterValue = parseBuiltinFilterArguments(args, filterType);
+            RefPtr<WebKitCSSFilterValue> filterValue = parseBuiltinFilterArguments(*args, filterType);
             if (!filterValue)
-                return 0;
+                return false;
             
-            list->append(filterValue);
+            list->append(filterValue.releaseNonNull());
         }
     }
 
-    return list.release();
+    result = list;
+
+    return true;
 }
-#endif
 
 #if ENABLE(CSS_REGIONS)
 static bool validFlowName(const String& flowName)
 {
-    return !(equalIgnoringCase(flowName, "auto")
-            || equalIgnoringCase(flowName, "default")
-            || equalIgnoringCase(flowName, "inherit")
-            || equalIgnoringCase(flowName, "initial")
-            || equalIgnoringCase(flowName, "none"));
+    return !(equalLettersIgnoringASCIICase(flowName, "auto")
+        || equalLettersIgnoringASCIICase(flowName, "default")
+        || equalLettersIgnoringASCIICase(flowName, "inherit")
+        || equalLettersIgnoringASCIICase(flowName, "initial")
+        || equalLettersIgnoringASCIICase(flowName, "none"));
 }
 #endif
 
@@ -9229,21 +10138,7 @@ bool CSSParser::cssCompositingEnabled() const
     return m_context.isCSSCompositingEnabled;
 }
 
-bool CSSParser::cssGridLayoutEnabled() const
-{
-    return m_context.isCSSGridLayoutEnabled;
-}
-
 #if ENABLE(CSS_REGIONS)
-bool CSSParser::parseFlowThread(const String& flowName)
-{
-    setupParser("@-webkit-decls{-webkit-flow-into:", flowName, "}");
-    cssyyparse(this);
-
-    m_rule = 0;
-
-    return ((m_parsedProperties.size() == 1) && (m_parsedProperties.first().id() == CSSPropertyWebkitFlowInto));
-}
 
 // none | <ident>
 bool CSSParser::parseFlowThread(CSSPropertyID propId, bool important)
@@ -9262,7 +10157,7 @@ bool CSSParser::parseFlowThread(CSSPropertyID propId, bool important)
         return false;
 
     if (value->id == CSSValueNone) {
-        addProperty(propId, cssValuePool().createIdentifierValue(value->id), important);
+        addProperty(propId, CSSValuePool::singleton().createIdentifierValue(value->id), important);
         return true;
     }
 
@@ -9270,9 +10165,9 @@ bool CSSParser::parseFlowThread(CSSPropertyID propId, bool important)
     if (!inputProperty.isEmpty()) {
         if (!validFlowName(inputProperty))
             return false;
-        addProperty(propId, cssValuePool().createValue(inputProperty, CSSPrimitiveValue::CSS_STRING), important);
+        addProperty(propId, CSSValuePool::singleton().createValue(inputProperty, CSSPrimitiveValue::CSS_STRING), important);
     } else
-        addProperty(propId, cssValuePool().createIdentifierValue(CSSValueNone), important);
+        addProperty(propId, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
 
     return true;
 }
@@ -9294,95 +10189,96 @@ bool CSSParser::parseRegionThread(CSSPropertyID propId, bool important)
         return false;
 
     if (value->id == CSSValueNone)
-        addProperty(propId, cssValuePool().createIdentifierValue(value->id), important);
+        addProperty(propId, CSSValuePool::singleton().createIdentifierValue(value->id), important);
     else {
         String inputProperty = String(value->string);
         if (!inputProperty.isEmpty()) {
             if (!validFlowName(inputProperty))
                 return false;
-            addProperty(propId, cssValuePool().createValue(inputProperty, CSSPrimitiveValue::CSS_STRING), important);
+            addProperty(propId, CSSValuePool::singleton().createValue(inputProperty, CSSPrimitiveValue::CSS_STRING), important);
         } else
-            addProperty(propId, cssValuePool().createIdentifierValue(CSSValueNone), important);
+            addProperty(propId, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
     }
 
     return true;
 }
 #endif
 
-bool CSSParser::parseTransformOrigin(CSSPropertyID propId, CSSPropertyID& propId1, CSSPropertyID& propId2, CSSPropertyID& propId3, RefPtr<CSSValue>& value, RefPtr<CSSValue>& value2, RefPtr<CSSValue>& value3)
+bool CSSParser::parseTransformOrigin(CSSPropertyID propId, CSSPropertyID& propId1, CSSPropertyID& propId2, CSSPropertyID& propId3, RefPtr<CSSPrimitiveValue>& value, RefPtr<CSSPrimitiveValue>& value2, RefPtr<CSSValue>& value3)
 {
     propId1 = propId;
     propId2 = propId;
     propId3 = propId;
-    if (propId == CSSPropertyWebkitTransformOrigin) {
-        propId1 = CSSPropertyWebkitTransformOriginX;
-        propId2 = CSSPropertyWebkitTransformOriginY;
-        propId3 = CSSPropertyWebkitTransformOriginZ;
+    if (propId == CSSPropertyTransformOrigin) {
+        propId1 = CSSPropertyTransformOriginX;
+        propId2 = CSSPropertyTransformOriginY;
+        propId3 = CSSPropertyTransformOriginZ;
     }
 
     switch (propId) {
-        case CSSPropertyWebkitTransformOrigin:
-            if (!parseTransformOriginShorthand(value, value2, value3))
-                return false;
-            // parseTransformOriginShorthand advances the m_valueList pointer
-            break;
-        case CSSPropertyWebkitTransformOriginX: {
-            value = parseFillPositionX(m_valueList.get());
-            if (value)
-                m_valueList->next();
-            break;
-        }
-        case CSSPropertyWebkitTransformOriginY: {
-            value = parseFillPositionY(m_valueList.get());
-            if (value)
-                m_valueList->next();
-            break;
-        }
-        case CSSPropertyWebkitTransformOriginZ: {
-            if (validUnit(m_valueList->current(), FLength))
-                value = createPrimitiveNumericValue(m_valueList->current());
-            if (value)
-                m_valueList->next();
-            break;
-        }
-        default:
-            ASSERT_NOT_REACHED();
+    case CSSPropertyTransformOrigin:
+        if (!parseTransformOriginShorthand(value, value2, value3))
             return false;
+        // parseTransformOriginShorthand advances the m_valueList pointer
+        break;
+    case CSSPropertyTransformOriginX: {
+        value = parsePositionX(*m_valueList);
+        if (value)
+            m_valueList->next();
+        break;
+    }
+    case CSSPropertyTransformOriginY: {
+        value = parsePositionY(*m_valueList);
+        if (value)
+            m_valueList->next();
+        break;
+    }
+    case CSSPropertyTransformOriginZ: {
+        ValueWithCalculation valueWithCalculation(*m_valueList->current());
+        if (validateUnit(valueWithCalculation, FLength))
+            value = createPrimitiveNumericValue(valueWithCalculation);
+        if (value)
+            m_valueList->next();
+        break;
+    }
+    default:
+        ASSERT_NOT_REACHED();
+        return false;
     }
 
     return value;
 }
 
-bool CSSParser::parsePerspectiveOrigin(CSSPropertyID propId, CSSPropertyID& propId1, CSSPropertyID& propId2, RefPtr<CSSValue>& value, RefPtr<CSSValue>& value2)
+bool CSSParser::parsePerspectiveOrigin(CSSPropertyID propId, CSSPropertyID& propId1, CSSPropertyID& propId2, RefPtr<CSSPrimitiveValue>& value, RefPtr<CSSPrimitiveValue>& value2)
 {
     propId1 = propId;
     propId2 = propId;
-    if (propId == CSSPropertyWebkitPerspectiveOrigin) {
-        propId1 = CSSPropertyWebkitPerspectiveOriginX;
-        propId2 = CSSPropertyWebkitPerspectiveOriginY;
+    if (propId == CSSPropertyPerspectiveOrigin) {
+        propId1 = CSSPropertyPerspectiveOriginX;
+        propId2 = CSSPropertyPerspectiveOriginY;
     }
 
     switch (propId) {
-        case CSSPropertyWebkitPerspectiveOrigin:
-            if (m_valueList->size() > 2)
-                return false;
-            parse2ValuesFillPosition(m_valueList.get(), value, value2);
-            break;
-        case CSSPropertyWebkitPerspectiveOriginX: {
-            value = parseFillPositionX(m_valueList.get());
-            if (value)
-                m_valueList->next();
-            break;
-        }
-        case CSSPropertyWebkitPerspectiveOriginY: {
-            value = parseFillPositionY(m_valueList.get());
-            if (value)
-                m_valueList->next();
-            break;
-        }
-        default:
-            ASSERT_NOT_REACHED();
+    case CSSPropertyPerspectiveOrigin:
+        if (m_valueList->size() > 2)
             return false;
+        parse2ValuesFillPosition(*m_valueList, value, value2);
+        break;
+    case CSSPropertyPerspectiveOriginX: {
+        value = parsePositionX(*m_valueList);
+        if (value)
+            m_valueList->next();
+        break;
+    }
+    case CSSPropertyPerspectiveOriginY: {
+        value = parsePositionY(*m_valueList);
+        if (value)
+            m_valueList->next();
+        break;
+    }
+    default:
+        ASSERT_NOT_REACHED();
+        return false;
     }
 
     return value;
@@ -9390,23 +10286,21 @@ bool CSSParser::parsePerspectiveOrigin(CSSPropertyID propId, CSSPropertyID& prop
 
 void CSSParser::addTextDecorationProperty(CSSPropertyID propId, PassRefPtr<CSSValue> value, bool important)
 {
-#if ENABLE(CSS3_TEXT)
     // The text-decoration-line property takes priority over text-decoration, unless the latter has important priority set.
-    if (propId == CSSPropertyTextDecoration && !important && m_currentShorthand == CSSPropertyInvalid) {
+    if (propId == CSSPropertyTextDecoration && !important && !inShorthand()) {
         for (unsigned i = 0; i < m_parsedProperties.size(); ++i) {
             if (m_parsedProperties[i].id() == CSSPropertyWebkitTextDecorationLine)
                 return;
         }
     }
-#endif // CSS3_TEXT
     addProperty(propId, value, important);
 }
 
 bool CSSParser::parseTextDecoration(CSSPropertyID propId, bool important)
 {
     CSSParserValue* value = m_valueList->current();
-    if (value->id == CSSValueNone) {
-        addTextDecorationProperty(propId, cssValuePool().createIdentifierValue(CSSValueNone), important);
+    if (value && value->id == CSSValueNone) {
+        addTextDecorationProperty(propId, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
         m_valueList->next();
         return true;
     }
@@ -9419,7 +10313,10 @@ bool CSSParser::parseTextDecoration(CSSPropertyID propId, bool important)
         case CSSValueLineThrough:
         case CSSValueOverline:
         case CSSValueUnderline:
-            list->append(cssValuePool().createIdentifierValue(value->id));
+#if ENABLE(LETTERPRESS)
+        case CSSValueWebkitLetterpress:
+#endif
+            list->append(CSSValuePool::singleton().createIdentifierValue(value->id));
             break;
         default:
             isValid = false;
@@ -9429,7 +10326,8 @@ bool CSSParser::parseTextDecoration(CSSPropertyID propId, bool important)
             value = m_valueList->next();
     }
 
-    if (list->length() && isValid) {
+    // Values are either valid or in shorthand scope.
+    if (list->length() && (isValid || inShorthand())) {
         addTextDecorationProperty(propId, list.release(), important);
         return true;
     }
@@ -9437,28 +10335,46 @@ bool CSSParser::parseTextDecoration(CSSPropertyID propId, bool important)
     return false;
 }
 
-#if ENABLE(CSS3_TEXT)
+bool CSSParser::parseTextDecorationSkip(bool important)
+{
+    // The text-decoration-skip property has syntax "none | [ objects || spaces || ink || edges || box-decoration ]".
+    // However, only 'none' and 'ink' are implemented yet, so we will parse syntax "none | ink" for now.
+    CSSParserValue* value = m_valueList->current();
+    do {
+        switch (value->id) {
+        case CSSValueNone:
+        case CSSValueAuto:
+        case CSSValueInk:
+        case CSSValueObjects:
+            addProperty(CSSPropertyWebkitTextDecorationSkip, CSSValuePool::singleton().createIdentifierValue(value->id), important);
+            return true;
+        default:
+            break;
+        }
+    } while ((value = m_valueList->next()));
+    return false;
+}
+
 bool CSSParser::parseTextUnderlinePosition(bool important)
 {
     // The text-underline-position property has sintax "auto | alphabetic | [ under || [ left | right ] ]".
     // However, values 'left' and 'right' are not implemented yet, so we will parse sintax
     // "auto | alphabetic | under" for now.
-    CSSParserValue* value = m_valueList->current();
-    switch (value->id) {
+    CSSParserValue& value = *m_valueList->current();
+    switch (value.id) {
     case CSSValueAuto:
     case CSSValueAlphabetic:
     case CSSValueUnder:
         if (m_valueList->next())
             return false;
 
-        addProperty(CSSPropertyWebkitTextUnderlinePosition, cssValuePool().createIdentifierValue(value->id), important);
+        addProperty(CSSPropertyWebkitTextUnderlinePosition, CSSValuePool::singleton().createIdentifierValue(value.id), important);
         return true;
     default:
         break;
     }
     return false;
 }
-#endif // CSS3_TEXT
 
 bool CSSParser::parseTextEmphasisStyle(bool important)
 {
@@ -9471,7 +10387,7 @@ bool CSSParser::parseTextEmphasisStyle(bool important)
         if (value->unit == CSSPrimitiveValue::CSS_STRING) {
             if (fill || shape || (valueListSize != 1 && !inShorthand()))
                 return false;
-            addProperty(CSSPropertyWebkitTextEmphasisStyle, createPrimitiveStringValue(value), important);
+            addProperty(CSSPropertyWebkitTextEmphasisStyle, createPrimitiveStringValue(*value), important);
             m_valueList->next();
             return true;
         }
@@ -9479,7 +10395,7 @@ bool CSSParser::parseTextEmphasisStyle(bool important)
         if (value->id == CSSValueNone) {
             if (fill || shape || (valueListSize != 1 && !inShorthand()))
                 return false;
-            addProperty(CSSPropertyWebkitTextEmphasisStyle, cssValuePool().createIdentifierValue(CSSValueNone), important);
+            addProperty(CSSPropertyWebkitTextEmphasisStyle, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
             m_valueList->next();
             return true;
         }
@@ -9487,11 +10403,11 @@ bool CSSParser::parseTextEmphasisStyle(bool important)
         if (value->id == CSSValueOpen || value->id == CSSValueFilled) {
             if (fill)
                 return false;
-            fill = cssValuePool().createIdentifierValue(value->id);
+            fill = CSSValuePool::singleton().createIdentifierValue(value->id);
         } else if (value->id == CSSValueDot || value->id == CSSValueCircle || value->id == CSSValueDoubleCircle || value->id == CSSValueTriangle || value->id == CSSValueSesame) {
             if (shape)
                 return false;
-            shape = cssValuePool().createIdentifierValue(value->id);
+            shape = CSSValuePool::singleton().createIdentifierValue(value->id);
         } else if (!inShorthand())
             return false;
         else
@@ -9500,8 +10416,8 @@ bool CSSParser::parseTextEmphasisStyle(bool important)
 
     if (fill && shape) {
         RefPtr<CSSValueList> parsedValues = CSSValueList::createSpaceSeparated();
-        parsedValues->append(fill.release());
-        parsedValues->append(shape.release());
+        parsedValues->append(fill.releaseNonNull());
+        parsedValues->append(shape.releaseNonNull());
         addProperty(CSSPropertyWebkitTextEmphasisStyle, parsedValues.release(), important);
         return true;
     }
@@ -9517,7 +10433,53 @@ bool CSSParser::parseTextEmphasisStyle(bool important)
     return false;
 }
 
-PassRefPtr<CSSValue> CSSParser::parseTextIndent()
+bool CSSParser::parseTextEmphasisPosition(bool important)
+{
+    bool foundOverOrUnder = false;
+    CSSValueID overUnderValueID = CSSValueOver;
+    bool foundLeftOrRight = false;
+    CSSValueID leftRightValueID = CSSValueRight;
+    for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
+        switch (value->id) {
+        case CSSValueOver:
+            if (foundOverOrUnder)
+                return false;
+            foundOverOrUnder = true;
+            overUnderValueID = CSSValueOver;
+            break;
+        case CSSValueUnder:
+            if (foundOverOrUnder)
+                return false;
+            foundOverOrUnder = true;
+            overUnderValueID = CSSValueUnder;
+            break;
+        case CSSValueLeft:
+            if (foundLeftOrRight)
+                return false;
+            foundLeftOrRight = true;
+            leftRightValueID = CSSValueLeft;
+            break;
+        case CSSValueRight:
+            if (foundLeftOrRight)
+                return false;
+            foundLeftOrRight = true;
+            leftRightValueID = CSSValueRight;
+            break;
+        default:
+            return false;
+        }
+    }
+    if (!foundOverOrUnder)
+        return false;
+    RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+    list->append(CSSValuePool::singleton().createIdentifierValue(overUnderValueID));
+    if (foundLeftOrRight)
+        list->append(CSSValuePool::singleton().createIdentifierValue(leftRightValueID));
+    addProperty(CSSPropertyWebkitTextEmphasisPosition, list, important);
+    return true;
+}
+
+RefPtr<CSSValue> CSSParser::parseTextIndent()
 {
     // <length> | <percentage> | inherit  when CSS3_TEXT is disabled.
     // [ <length> | <percentage> ] && [ -webkit-hanging || -webkit-each-line ]? | inherit  when CSS3_TEXT is enabled.
@@ -9530,31 +10492,76 @@ PassRefPtr<CSSValue> CSSParser::parseTextIndent()
 
     CSSParserValue* value = m_valueList->current();
     while (value) {
-        if (!hasLengthOrPercentage && validUnit(value, FLength | FPercent)) {
-            list->append(createPrimitiveNumericValue(value));
+        ValueWithCalculation valueWithCalculation(*value);
+        if (!hasLengthOrPercentage && validateUnit(valueWithCalculation, FLength | FPercent)) {
+            list->append(createPrimitiveNumericValue(valueWithCalculation));
             hasLengthOrPercentage = true;
         }
 #if ENABLE(CSS3_TEXT)
         else if (!hasEachLine && value->id == CSSValueWebkitEachLine) {
-            list->append(cssValuePool().createIdentifierValue(CSSValueWebkitEachLine));
+            list->append(CSSValuePool::singleton().createIdentifierValue(CSSValueWebkitEachLine));
             hasEachLine = true;
         } else if (!hasHanging && value->id == CSSValueWebkitHanging) {
-            list->append(cssValuePool().createIdentifierValue(CSSValueWebkitHanging));
+            list->append(CSSValuePool::singleton().createIdentifierValue(CSSValueWebkitHanging));
             hasHanging = true;
         }
 #endif
         else
-            return 0;
+            return nullptr;
 
         value = m_valueList->next();
     }
 
     if (!hasLengthOrPercentage)
-        return 0;
+        return nullptr;
 
     return list.release();
 }
 
+bool CSSParser::parseHangingPunctuation(bool important)
+{
+    CSSParserValue* value = m_valueList->current();
+    if (value && value->id == CSSValueNone) {
+        addProperty(CSSPropertyHangingPunctuation, CSSValuePool::singleton().createIdentifierValue(CSSValueNone), important);
+        m_valueList->next();
+        return true;
+    }
+    
+    RefPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+    bool isValid = true;
+    std::bitset<numCSSValueKeywords> seenValues;
+    while (isValid && value) {
+        if (seenValues[value->id]
+            || (value->id == CSSValueAllowEnd && seenValues[CSSValueForceEnd])
+            || (value->id == CSSValueForceEnd && seenValues[CSSValueAllowEnd])) {
+            isValid = false;
+            break;
+        }
+        switch (value->id) {
+        case CSSValueAllowEnd:
+        case CSSValueFirst:
+        case CSSValueForceEnd:
+        case CSSValueLast:
+            list->append(CSSValuePool::singleton().createIdentifierValue(value->id));
+            seenValues.set(value->id);
+            break;
+        default:
+            isValid = false;
+            break;
+        }
+        if (isValid)
+            value = m_valueList->next();
+    }
+    
+    // Values are either valid or in shorthand scope.
+    if (list->length() && isValid) {
+        addProperty(CSSPropertyHangingPunctuation, list.release(), important);
+        return true;
+    }
+    
+    return false;
+}
+
 bool CSSParser::parseLineBoxContain(bool important)
 {
     LineBoxContain lineBoxContain = LineBoxContainNone;
@@ -9584,6 +10591,10 @@ bool CSSParser::parseLineBoxContain(bool important)
             if (lineBoxContain & LineBoxContainInlineBox)
                 return false;
             lineBoxContain |= LineBoxContainInlineBox;
+        } else if (value->id == CSSValueInitialLetter) {
+            if (lineBoxContain & LineBoxContainInitialLetter)
+                return false;
+            lineBoxContain |= LineBoxContainInitialLetter;
         } else
             return false;
     }
@@ -9595,25 +10606,23 @@ bool CSSParser::parseLineBoxContain(bool important)
     return true;
 }
 
-bool CSSParser::parseFontFeatureTag(CSSValueList* settings)
+bool CSSParser::parseFontFeatureTag(CSSValueList& settings)
 {
-    // Feature tag name consists of 4-letter characters.
-    static const unsigned tagNameLength = 4;
-
     CSSParserValue* value = m_valueList->current();
     // Feature tag name comes first
     if (value->unit != CSSPrimitiveValue::CSS_STRING)
         return false;
-    if (value->string.length() != tagNameLength)
+    FontFeatureTag tag;
+    if (value->string.length() != tag.size())
         return false;
-    for (unsigned i = 0; i < tagNameLength; ++i) {
+    for (unsigned i = 0; i < tag.size(); ++i) {
         // Limits the range of characters to 0x20-0x7E, following the tag name rules defiend in the OpenType specification.
         UChar character = value->string[i];
         if (character < 0x20 || character > 0x7E)
             return false;
+        tag[i] = toASCIILower(character);
     }
 
-    String tag = value->string;
     int tagValue = 1;
     // Feature tag values could follow: <integer> | on | off
     value = m_valueList->next();
@@ -9628,22 +10637,22 @@ bool CSSParser::parseFontFeatureTag(CSSValueList* settings)
             m_valueList->next();
         }
     }
-    settings->append(FontFeatureValue::create(tag, tagValue));
+    settings.append(CSSFontFeatureValue::create(WTFMove(tag), tagValue));
     return true;
 }
 
 bool CSSParser::parseFontFeatureSettings(bool important)
 {
     if (m_valueList->size() == 1 && m_valueList->current()->id == CSSValueNormal) {
-        RefPtr<CSSPrimitiveValue> normalValue = cssValuePool().createIdentifierValue(CSSValueNormal);
+        RefPtr<CSSPrimitiveValue> normalValue = CSSValuePool::singleton().createIdentifierValue(CSSValueNormal);
         m_valueList->next();
-        addProperty(CSSPropertyWebkitFontFeatureSettings, normalValue.release(), important);
+        addProperty(CSSPropertyFontFeatureSettings, normalValue.release(), important);
         return true;
     }
 
     RefPtr<CSSValueList> settings = CSSValueList::createCommaSeparated();
     for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
-        if (!parseFontFeatureTag(settings.get()))
+        if (!parseFontFeatureTag(*settings))
             return false;
 
         // If the list isn't parsed fully, the current value should be comma.
@@ -9652,18 +10661,19 @@ bool CSSParser::parseFontFeatureSettings(bool important)
             return false;
     }
     if (settings->length()) {
-        addProperty(CSSPropertyWebkitFontFeatureSettings, settings.release(), important);
+        addProperty(CSSPropertyFontFeatureSettings, settings.release(), important);
         return true;
     }
     return false;
 }
 
-bool CSSParser::parseFontVariantLigatures(bool important)
+bool CSSParser::parseFontVariantLigatures(bool important, bool unknownIsFailure, bool implicit)
 {
-    RefPtr<CSSValueList> ligatureValues = CSSValueList::createSpaceSeparated();
-    bool sawCommonLigaturesValue = false;
-    bool sawDiscretionaryLigaturesValue = false;
-    bool sawHistoricalLigaturesValue = false;
+    auto values = CSSValueList::createSpaceSeparated();
+    FontVariantLigatures commonLigatures = FontVariantLigatures::Normal;
+    FontVariantLigatures discretionaryLigatures = FontVariantLigatures::Normal;
+    FontVariantLigatures historicalLigatures = FontVariantLigatures::Normal;
+    FontVariantLigatures contextualAlternates = FontVariantLigatures::Normal;
 
     for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
         if (value->unit != CSSPrimitiveValue::CSS_IDENT)
@@ -9671,55 +10681,471 @@ bool CSSParser::parseFontVariantLigatures(bool important)
 
         switch (value->id) {
         case CSSValueNoCommonLigatures:
+            commonLigatures = FontVariantLigatures::No;
+            break;
         case CSSValueCommonLigatures:
-            if (sawCommonLigaturesValue)
-                return false;
-            sawCommonLigaturesValue = true;
-            ligatureValues->append(cssValuePool().createIdentifierValue(value->id));
+            commonLigatures = FontVariantLigatures::Yes;
             break;
         case CSSValueNoDiscretionaryLigatures:
+            discretionaryLigatures = FontVariantLigatures::No;
+            break;
         case CSSValueDiscretionaryLigatures:
-            if (sawDiscretionaryLigaturesValue)
-                return false;
-            sawDiscretionaryLigaturesValue = true;
-            ligatureValues->append(cssValuePool().createIdentifierValue(value->id));
+            discretionaryLigatures = FontVariantLigatures::Yes;
             break;
         case CSSValueNoHistoricalLigatures:
+            historicalLigatures = FontVariantLigatures::No;
+            break;
         case CSSValueHistoricalLigatures:
-            if (sawHistoricalLigaturesValue)
+            historicalLigatures = FontVariantLigatures::Yes;
+            break;
+        case CSSValueContextual:
+            contextualAlternates = FontVariantLigatures::Yes;
+            break;
+        case CSSValueNoContextual:
+            contextualAlternates = FontVariantLigatures::No;
+            break;
+        default:
+            if (unknownIsFailure)
                 return false;
-            sawHistoricalLigaturesValue = true;
-            ligatureValues->append(cssValuePool().createIdentifierValue(value->id));
+            continue;
+        }
+    }
+
+    switch (commonLigatures) {
+    case FontVariantLigatures::Normal:
+        break;
+    case FontVariantLigatures::Yes:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueCommonLigatures));
+        break;
+    case FontVariantLigatures::No:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueNoCommonLigatures));
+        break;
+    }
+
+    switch (discretionaryLigatures) {
+    case FontVariantLigatures::Normal:
+        break;
+    case FontVariantLigatures::Yes:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueDiscretionaryLigatures));
+        break;
+    case FontVariantLigatures::No:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueNoDiscretionaryLigatures));
+        break;
+    }
+
+    switch (historicalLigatures) {
+    case FontVariantLigatures::Normal:
+        break;
+    case FontVariantLigatures::Yes:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueHistoricalLigatures));
+        break;
+    case FontVariantLigatures::No:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueNoHistoricalLigatures));
+        break;
+    }
+
+    switch (contextualAlternates) {
+    case FontVariantLigatures::Normal:
+        break;
+    case FontVariantLigatures::Yes:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueContextual));
+        break;
+    case FontVariantLigatures::No:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueNoContextual));
+        break;
+    }
+
+    if (!values->length())
+        return !unknownIsFailure;
+
+    addProperty(CSSPropertyFontVariantLigatures, WTFMove(values), important, implicit);
+    return true;
+}
+
+bool CSSParser::parseFontVariantNumeric(bool important, bool unknownIsFailure, bool implicit)
+{
+    auto values = CSSValueList::createSpaceSeparated();
+    FontVariantNumericFigure figure = FontVariantNumericFigure::Normal;
+    FontVariantNumericSpacing spacing = FontVariantNumericSpacing::Normal;
+    FontVariantNumericFraction fraction = FontVariantNumericFraction::Normal;
+    FontVariantNumericOrdinal ordinal = FontVariantNumericOrdinal::Normal;
+    FontVariantNumericSlashedZero slashedZero = FontVariantNumericSlashedZero::Normal;
+
+    for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
+        if (value->unit != CSSPrimitiveValue::CSS_IDENT)
+            return false;
+
+        switch (value->id) {
+        case CSSValueLiningNums:
+            figure = FontVariantNumericFigure::LiningNumbers;
+            break;
+        case CSSValueOldstyleNums:
+            figure = FontVariantNumericFigure::OldStyleNumbers;
+            break;
+        case CSSValueProportionalNums:
+            spacing = FontVariantNumericSpacing::ProportionalNumbers;
+            break;
+        case CSSValueTabularNums:
+            spacing = FontVariantNumericSpacing::TabularNumbers;
+            break;
+        case CSSValueDiagonalFractions:
+            fraction = FontVariantNumericFraction::DiagonalFractions;
+            break;
+        case CSSValueStackedFractions:
+            fraction = FontVariantNumericFraction::StackedFractions;
+            break;
+        case CSSValueOrdinal:
+            ordinal = FontVariantNumericOrdinal::Yes;
+            break;
+        case CSSValueSlashedZero:
+            slashedZero = FontVariantNumericSlashedZero::Yes;
             break;
         default:
+            if (unknownIsFailure)
+                return false;
+            continue;
+        }
+    }
+
+    switch (figure) {
+    case FontVariantNumericFigure::Normal:
+        break;
+    case FontVariantNumericFigure::LiningNumbers:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueLiningNums));
+        break;
+    case FontVariantNumericFigure::OldStyleNumbers:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueOldstyleNums));
+        break;
+    }
+
+    switch (spacing) {
+    case FontVariantNumericSpacing::Normal:
+        break;
+    case FontVariantNumericSpacing::ProportionalNumbers:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueProportionalNums));
+        break;
+    case FontVariantNumericSpacing::TabularNumbers:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueTabularNums));
+        break;
+    }
+
+    switch (fraction) {
+    case FontVariantNumericFraction::Normal:
+        break;
+    case FontVariantNumericFraction::DiagonalFractions:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueDiagonalFractions));
+        break;
+    case FontVariantNumericFraction::StackedFractions:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueStackedFractions));
+        break;
+    }
+
+    switch (ordinal) {
+    case FontVariantNumericOrdinal::Normal:
+        break;
+    case FontVariantNumericOrdinal::Yes:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueOrdinal));
+        break;
+    }
+
+    switch (slashedZero) {
+    case FontVariantNumericSlashedZero::Normal:
+        break;
+    case FontVariantNumericSlashedZero::Yes:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueSlashedZero));
+        break;
+    }
+
+    if (!values->length())
+        return !unknownIsFailure;
+
+    addProperty(CSSPropertyFontVariantNumeric, WTFMove(values), important, implicit);
+    return true;
+}
+
+bool CSSParser::parseFontVariantEastAsian(bool important, bool unknownIsFailure, bool implicit)
+{
+    auto values = CSSValueList::createSpaceSeparated();
+    FontVariantEastAsianVariant variant = FontVariantEastAsianVariant::Normal;
+    FontVariantEastAsianWidth width = FontVariantEastAsianWidth::Normal;
+    FontVariantEastAsianRuby ruby = FontVariantEastAsianRuby::Normal;
+
+    for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
+        if (value->unit != CSSPrimitiveValue::CSS_IDENT)
             return false;
+
+        switch (value->id) {
+        case CSSValueJis78:
+            variant = FontVariantEastAsianVariant::Jis78;
+            break;
+        case CSSValueJis83:
+            variant = FontVariantEastAsianVariant::Jis83;
+            break;
+        case CSSValueJis90:
+            variant = FontVariantEastAsianVariant::Jis90;
+            break;
+        case CSSValueJis04:
+            variant = FontVariantEastAsianVariant::Jis04;
+            break;
+        case CSSValueSimplified:
+            variant = FontVariantEastAsianVariant::Simplified;
+            break;
+        case CSSValueTraditional:
+            variant = FontVariantEastAsianVariant::Traditional;
+            break;
+        case CSSValueFullWidth:
+            width = FontVariantEastAsianWidth::Full;
+            break;
+        case CSSValueProportionalWidth:
+            width = FontVariantEastAsianWidth::Proportional;
+            break;
+        case CSSValueRuby:
+            ruby = FontVariantEastAsianRuby::Yes;
+            break;
+        default:
+            if (unknownIsFailure)
+                return false;
+            continue;
         }
     }
 
-    if (!ligatureValues->length())
+    switch (variant) {
+    case FontVariantEastAsianVariant::Normal:
+        break;
+    case FontVariantEastAsianVariant::Jis78:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueJis78));
+        break;
+    case FontVariantEastAsianVariant::Jis83:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueJis83));
+        break;
+    case FontVariantEastAsianVariant::Jis90:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueJis90));
+        break;
+    case FontVariantEastAsianVariant::Jis04:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueJis04));
+        break;
+    case FontVariantEastAsianVariant::Simplified:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueSimplified));
+        break;
+    case FontVariantEastAsianVariant::Traditional:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueTraditional));
+        break;
+    }
+
+    switch (width) {
+    case FontVariantEastAsianWidth::Normal:
+        break;
+    case FontVariantEastAsianWidth::Full:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueFullWidth));
+        break;
+    case FontVariantEastAsianWidth::Proportional:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueProportionalWidth));
+        break;
+    }
+
+    switch (ruby) {
+    case FontVariantEastAsianRuby::Normal:
+        break;
+    case FontVariantEastAsianRuby::Yes:
+        values->append(CSSValuePool::singleton().createIdentifierValue(CSSValueRuby));
+    }
+
+    if (!values->length())
+        return !unknownIsFailure;
+
+    addProperty(CSSPropertyFontVariantEastAsian, WTFMove(values), important, implicit);
+    return true;
+}
+
+bool CSSParser::parseFontVariant(bool important)
+{
+    ShorthandScope scope(this, CSSPropertyFontVariant);
+    if (!parseFontVariantLigatures(important, false, false))
+        return false;
+    m_valueList->setCurrentIndex(0);
+    if (!parseFontVariantNumeric(important, false, false))
+        return false;
+    m_valueList->setCurrentIndex(0);
+    if (!parseFontVariantEastAsian(important, false, false))
         return false;
+    m_valueList->setCurrentIndex(0);
+
+    FontVariantPosition position = FontVariantPosition::Normal;
+    FontVariantCaps caps = FontVariantCaps::Normal;
+    FontVariantAlternates alternates = FontVariantAlternates::Normal;
+
+    for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
+        if (value->unit != CSSPrimitiveValue::CSS_IDENT)
+            return false;
+
+        switch (value->id) {
+        case CSSValueNoCommonLigatures:
+        case CSSValueCommonLigatures:
+        case CSSValueNoDiscretionaryLigatures:
+        case CSSValueDiscretionaryLigatures:
+        case CSSValueNoHistoricalLigatures:
+        case CSSValueHistoricalLigatures:
+        case CSSValueContextual:
+        case CSSValueNoContextual:
+        case CSSValueLiningNums:
+        case CSSValueOldstyleNums:
+        case CSSValueProportionalNums:
+        case CSSValueTabularNums:
+        case CSSValueDiagonalFractions:
+        case CSSValueStackedFractions:
+        case CSSValueOrdinal:
+        case CSSValueSlashedZero:
+        case CSSValueJis78:
+        case CSSValueJis83:
+        case CSSValueJis90:
+        case CSSValueJis04:
+        case CSSValueSimplified:
+        case CSSValueTraditional:
+        case CSSValueFullWidth:
+        case CSSValueProportionalWidth:
+        case CSSValueRuby:
+            break;
+        case CSSValueSub:
+            position = FontVariantPosition::Subscript;
+            break;
+        case CSSValueSuper:
+            position = FontVariantPosition::Superscript;
+            break;
+        case CSSValueSmallCaps:
+            caps = FontVariantCaps::Small;
+            break;
+        case CSSValueAllSmallCaps:
+            caps = FontVariantCaps::AllSmall;
+            break;
+        case CSSValuePetiteCaps:
+            caps = FontVariantCaps::Petite;
+            break;
+        case CSSValueAllPetiteCaps:
+            caps = FontVariantCaps::AllPetite;
+            break;
+        case CSSValueUnicase:
+            caps = FontVariantCaps::Unicase;
+            break;
+        case CSSValueTitlingCaps:
+            caps = FontVariantCaps::Titling;
+            break;
+        case CSSValueHistoricalForms:
+            alternates = FontVariantAlternates::HistoricalForms;
+            break;
+        default:
+            return false;
+        }
+    }
+
+    switch (position) {
+    case FontVariantPosition::Normal:
+        break;
+    case FontVariantPosition::Subscript:
+        addProperty(CSSPropertyFontVariantPosition, CSSValuePool::singleton().createIdentifierValue(CSSValueSub), important, false);
+        break;
+    case FontVariantPosition::Superscript:
+        addProperty(CSSPropertyFontVariantPosition, CSSValuePool::singleton().createIdentifierValue(CSSValueSuper), important, false);
+        break;
+    }
+
+    switch (caps) {
+    case FontVariantCaps::Normal:
+        break;
+    case FontVariantCaps::Small:
+        addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueSmallCaps), important, false);
+        break;
+    case FontVariantCaps::AllSmall:
+        addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueAllSmallCaps), important, false);
+        break;
+    case FontVariantCaps::Petite:
+        addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValuePetiteCaps), important, false);
+        break;
+    case FontVariantCaps::AllPetite:
+        addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueAllPetiteCaps), important, false);
+        break;
+    case FontVariantCaps::Unicase:
+        addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueUnicase), important, false);
+        break;
+    case FontVariantCaps::Titling:
+        addProperty(CSSPropertyFontVariantCaps, CSSValuePool::singleton().createIdentifierValue(CSSValueTitlingCaps), important, false);
+        break;
+    }
+
+    switch (alternates) {
+    case FontVariantAlternates::Normal:
+        break;
+    case FontVariantAlternates::HistoricalForms:
+        addProperty(CSSPropertyFontVariantAlternates, CSSValuePool::singleton().createIdentifierValue(CSSValueHistoricalForms), important, false);
+        break;
+    }
 
-    addProperty(CSSPropertyWebkitFontVariantLigatures, ligatureValues.release(), important);
     return true;
 }
 
-bool CSSParser::parseCalculation(CSSParserValue* value, CalculationPermittedValueRange range) 
+static inline bool isValidWillChangeAnimatableFeature(const CSSParserValue& value)
 {
-    ASSERT(isCalculation(value));
-    
-    CSSParserValueList* args = value->function->args.get();
-    if (!args || !args->size())
+    if (value.id == CSSValueNone || value.id == CSSValueAuto || value.id == CSSValueAll)
         return false;
 
-    ASSERT(!m_parsedCalculation);
-    m_parsedCalculation = CSSCalcValue::create(value->function->name, args, range);
-    
-    if (!m_parsedCalculation)
+    if (valueIsCSSKeyword(value))
         return false;
-    
+
+    if (cssPropertyID(value.string) == CSSPropertyWillChange)
+        return false;
+
     return true;
 }
 
+bool CSSParser::parseWillChange(bool important)
+{
+    RefPtr<CSSValueList> willChangePropertyValues = CSSValueList::createCommaSeparated();
+
+    bool expectComma = false;
+    for (CSSParserValue* value = m_valueList->current(); value; value = m_valueList->next()) {
+        if (expectComma) {
+            if (!isComma(value))
+                return false;
+            
+            expectComma = false;
+            continue;
+        }
+
+        if (value->unit != CSSPrimitiveValue::CSS_IDENT)
+            return false;
+
+        if (!isValidWillChangeAnimatableFeature(*value))
+            return false;
+
+        RefPtr<CSSValue> cssValue;
+        if (value->id == CSSValueScrollPosition || value->id == CSSValueContents)
+            cssValue = CSSValuePool::singleton().createIdentifierValue(value->id);
+        else {
+            CSSPropertyID propertyID = cssPropertyID(value->string);
+            if (propertyID != CSSPropertyInvalid)
+                cssValue = CSSValuePool::singleton().createIdentifierValue(propertyID);
+            else // This might be a property we don't support.
+                cssValue = createPrimitiveStringValue(*value);
+        }
+
+        willChangePropertyValues->append(cssValue.releaseNonNull());
+        expectComma = true;
+    }
+
+    addProperty(CSSPropertyWillChange, willChangePropertyValues.release(), important);
+    return true;
+}
+
+RefPtr<CSSCalcValue> CSSParser::parseCalculation(CSSParserValue& value, CalculationPermittedValueRange range)
+{
+    ASSERT(isCalculation(value));
+    
+    CSSParserValueList* args = value.function->args.get();
+    if (!args || !args->size())
+        return nullptr;
+
+    return CSSCalcValue::create(value.function->name, *args, range);
+}
+
 #define END_TOKEN 0
 
 #include "CSSGrammar.h"
@@ -9737,7 +11163,7 @@ enum CharacterType {
     CharacterOther,
     CharacterNull,
     CharacterWhiteSpace,
-    CharacterEndMediaQuery,
+    CharacterEndConditionQuery,
     CharacterEndNthChild,
     CharacterQuote,
     CharacterExclamationMark,
@@ -9816,7 +11242,7 @@ static const CharacterType typesOfASCIICharacters[128] = {
 /*  56 - 8                  */ CharacterNumber,
 /*  57 - 9                  */ CharacterNumber,
 /*  58 - :                  */ CharacterOther,
-/*  59 - ;                  */ CharacterEndMediaQuery,
+/*  59 - ;                  */ CharacterEndConditionQuery,
 /*  60 - <                  */ CharacterLess,
 /*  61 - =                  */ CharacterOther,
 /*  62 - >                  */ CharacterOther,
@@ -9880,7 +11306,7 @@ static const CharacterType typesOfASCIICharacters[128] = {
 /* 120 - x                  */ CharacterIdentifierStart,
 /* 121 - y                  */ CharacterIdentifierStart,
 /* 122 - z                  */ CharacterIdentifierStart,
-/* 123 - {                  */ CharacterEndMediaQuery,
+/* 123 - {                  */ CharacterEndConditionQuery,
 /* 124 - |                  */ CharacterVerticalBar,
 /* 125 - }                  */ CharacterOther,
 /* 126 - ~                  */ CharacterTilde,
@@ -9915,6 +11341,13 @@ static inline bool isIdentifierStartAfterDash(CharacterType* currentCharacter)
 }
 
 template <typename CharacterType>
+static inline bool isCustomPropertyIdentifier(CharacterType* currentCharacter)
+{
+    return isASCIIAlpha(currentCharacter[0]) || currentCharacter[0] == '_' || currentCharacter[0] >= 128
+        || (currentCharacter[0] == '\\' && isCSSEscape(currentCharacter[1]));
+}
+
+template <typename CharacterType>
 static inline bool isEqualToCSSIdentifier(CharacterType* cssString, const char* constantString)
 {
     // Compare an character memory data with a zero terminated string.
@@ -9948,7 +11381,7 @@ static CharacterType* checkAndSkipEscape(CharacterType* currentCharacter)
 
     ++currentCharacter;
     if (!isCSSEscape(*currentCharacter))
-        return 0;
+        return nullptr;
 
     if (isASCIIHexDigit(*currentCharacter)) {
         int length = 6;
@@ -9996,7 +11429,7 @@ inline UChar*& CSSParser::currentCharacter<UChar>()
 UChar*& CSSParser::currentCharacter16()
 {
     if (!m_currentCharacter16) {
-        m_dataStart16 = adoptArrayPtr(new UChar[m_length]);
+        m_dataStart16 = std::make_unique<UChar[]>(m_length);
         m_currentCharacter16 = m_dataStart16.get();
     }
 
@@ -10019,10 +11452,19 @@ CSSParser::Location CSSParser::currentLocation()
 {
     Location location;
     location.lineNumber = m_tokenStartLineNumber;
+    location.columnNumber = m_tokenStartColumnNumber;
+
+    ASSERT(location.lineNumber >= 0);
+    ASSERT(location.columnNumber >= 0);
+
+    if (location.lineNumber == m_sheetStartLineNumber)
+        location.columnNumber += m_sheetStartColumnNumber;
+
     if (is8BitSource())
         location.token.init(tokenStart<LChar>(), currentCharacter<LChar>() - tokenStart<LChar>());
     else
         location.token.init(tokenStart<UChar>(), currentCharacter<UChar>() - tokenStart<UChar>());
+
     return location;
 }
 
@@ -10051,7 +11493,7 @@ static inline CharacterType* checkAndSkipString(CharacterType* currentCharacter,
         }
         if (UNLIKELY(*currentCharacter <= '\r' && (*currentCharacter == '\n' || (*currentCharacter | 0x1) == '\r'))) {
             // String parsing is failed for character '\n', '\f' or '\r'.
-            return 0;
+            return nullptr;
         }
 
         if (LIKELY(currentCharacter[0] != '\\'))
@@ -10063,7 +11505,7 @@ static inline CharacterType* checkAndSkipString(CharacterType* currentCharacter,
         else {
             currentCharacter = checkAndSkipEscape(currentCharacter);
             if (!currentCharacter)
-                return 0;
+                return nullptr;
         }
     }
 }
@@ -10084,9 +11526,8 @@ unsigned CSSParser::parseEscape(CharacterType*& src)
             unicode = (unicode << 4) + toASCIIHexValue(*src++);
         } while (--length && isASCIIHexDigit(*src));
 
-        // Characters above 0x10ffff are not handled.
-        if (unicode > 0x10ffff)
-            unicode = 0xfffd;
+        if (unicode > UCHAR_MAX_VALUE)
+            unicode = replacementCharacter;
 
         // Optional space after the escape sequence.
         if (isHTMLSpace(*src))
@@ -10145,10 +11586,6 @@ inline bool CSSParser::parseIdentifierInternal(SrcCharacterType*& src, DestChara
 template <typename CharacterType>
 inline void CSSParser::parseIdentifier(CharacterType*& result, CSSParserString& resultString, bool& hasEscape)
 {
-    // If a valid identifier start is found, we can safely
-    // parse the identifier until the next invalid character.
-    ASSERT(isIdentifierStart<CharacterType>());
-
     CharacterType* start = currentCharacter<CharacterType>();
     if (UNLIKELY(!parseIdentifierInternal(currentCharacter<CharacterType>(), result, hasEscape))) {
         // Found an escape we couldn't handle with 8 bits, copy what has been recognized and continue
@@ -10156,13 +11593,14 @@ inline void CSSParser::parseIdentifier(CharacterType*& result, CSSParserString&
         UChar*& result16 = currentCharacter16();
         UChar* start16 = result16;
         int i = 0;
-        for (; i < result - start; i++)
+        for (; i < result - start; ++i)
             result16[i] = start[i];
 
         result16 += i;
 
         parseIdentifierInternal(currentCharacter<CharacterType>(), result16, hasEscape);
 
+        result += result16 - start16;
         resultString.init(start16, result16 - start16);
 
         return;
@@ -10217,7 +11655,7 @@ inline void CSSParser::parseString(CharacterType*& result, CSSParserString& resu
         UChar*& result16 = currentCharacter16();
         UChar* start16 = result16;
         int i = 0;
-        for (; i < result - start; i++)
+        for (; i < result - start; ++i)
             result16[i] = start[i];
 
         result16 += i;
@@ -10399,12 +11837,22 @@ inline bool CSSParser::detectFunctionTypeToken(int length)
             m_token = URI;
             return true;
         }
+        if (isASCIIAlphaCaselessEqual(name[0], 'v') && isASCIIAlphaCaselessEqual(name[1], 'a') && isASCIIAlphaCaselessEqual(name[2], 'r')) {
+            m_token = VARFUNCTION;
+            return true;
+        }
 #if ENABLE(VIDEO_TRACK)
         if (isASCIIAlphaCaselessEqual(name[0], 'c') && isASCIIAlphaCaselessEqual(name[1], 'u') && isASCIIAlphaCaselessEqual(name[2], 'e')) {
             m_token = CUEFUNCTION;
             return true;
         }
 #endif
+#if ENABLE(CSS_SELECTORS_LEVEL4)
+        if (isASCIIAlphaCaselessEqual(name[0], 'd') && isASCIIAlphaCaselessEqual(name[1], 'i') && isASCIIAlphaCaselessEqual(name[2], 'r')) {
+            m_token = DIRFUNCTION;
+            return true;
+        }
+#endif
         return false;
 
     case 4:
@@ -10412,10 +11860,28 @@ inline bool CSSParser::detectFunctionTypeToken(int length)
             m_token = CALCFUNCTION;
             return true;
         }
+        if (isEqualToCSSIdentifier(name, "lang")) {
+            m_token = LANGFUNCTION;
+            return true;
+        }
+#if ENABLE(CSS_SELECTORS_LEVEL4)
+        if (isEqualToCSSIdentifier(name, "role")) {
+            m_token = ROLEFUNCTION;
+            return true;
+        }
+#endif
+        return false;
+
+    case 7:
+        if (isEqualToCSSIdentifier(name, "matches")) {
+            m_token = MATCHESFUNCTION;
+            return true;
+        }
         return false;
 
     case 9:
         if (isEqualToCSSIdentifier(name, "nth-child")) {
+            m_token = NTHCHILDFUNCTIONS;
             m_parsingMode = NthChildMode;
             return true;
         }
@@ -10430,6 +11896,7 @@ inline bool CSSParser::detectFunctionTypeToken(int length)
 
     case 14:
         if (isEqualToCSSIdentifier(name, "nth-last-child")) {
+            m_token = NTHCHILDFUNCTIONS;
             m_parsingMode = NthChildMode;
             return true;
         }
@@ -10505,6 +11972,10 @@ inline void CSSParser::detectNumberToken(CharacterType* type, int length)
         }
         return;
 
+    case 'f':
+        if (length == 2 && isASCIIAlphaCaselessEqual(type[1], 'r'))
+            m_token = FR;
+        return;
     case 'g':
         if (length == 4 && isASCIIAlphaCaselessEqual(type[1], 'r')
                 && isASCIIAlphaCaselessEqual(type[2], 'a') && isASCIIAlphaCaselessEqual(type[3], 'd'))
@@ -10599,16 +12070,8 @@ inline void CSSParser::detectDashToken(int length)
             m_token = MINFUNCTION;
         else if (isASCIIAlphaCaselessEqual(name[10], 'x') && isEqualToCSSIdentifier(name + 1, "webkit-ma"))
             m_token = MAXFUNCTION;
-#if ENABLE(CSS_VARIABLES)
-        else if (cssVariablesEnabled() && isASCIIAlphaCaselessEqual(name[10], 'r') && isEqualToCSSIdentifier(name + 1, "webkit-va"))
-            m_token = VARFUNCTION;
-#endif
     } else if (length == 12 && isEqualToCSSIdentifier(name + 1, "webkit-calc"))
         m_token = CALCFUNCTION;
-#if ENABLE(SHADOW_DOM)
-    else if (length == 19 && isEqualToCSSIdentifier(name + 1, "webkit-distributed"))
-        m_token = DISTRIBUTEDFUNCTION;
-#endif
 }
 
 template <typename CharacterType>
@@ -10662,13 +12125,6 @@ inline void CSSParser::detectAtToken(int length, bool hasEscape)
             m_token = FONT_FACE_SYM;
         return;
 
-#if ENABLE(SHADOW_DOM)
-    case 'h':
-        if (length == 5 && isEqualToCSSIdentifier(name + 2, "ost"))
-            m_token = HOST_SYM;
-        return;
-#endif
-
     case 'i':
         if (length == 7 && isEqualToCSSIdentifier(name + 2, "mport")) {
             m_parsingMode = MediaQueryMode;
@@ -10676,6 +12132,13 @@ inline void CSSParser::detectAtToken(int length, bool hasEscape)
         }
         return;
 
+    case 'k':
+        if (length == 10 && isEqualToCSSIdentifier(name + 2, "eyframes"))
+            m_token = KEYFRAMES_SYM;
+        else if (length == 14 && !hasEscape && isEqualToCSSIdentifier(name + 2, "eyframe-rule"))
+            m_token = KEYFRAME_RULE_SYM;
+        return;
+
     case 'l':
         if (hasEscape)
             return;
@@ -10725,14 +12188,12 @@ inline void CSSParser::detectAtToken(int length, bool hasEscape)
         }
         return;
 
-#if ENABLE(CSS3_CONDITIONAL_RULES)
     case 's':
         if (length == 9 && isEqualToCSSIdentifier(name + 2, "upports")) {
             m_parsingMode = SupportsMode;
             m_token = SUPPORTS_SYM;
         }
         return;
-#endif
 
     case 't':
         if (hasEscape)
@@ -10789,16 +12250,8 @@ inline void CSSParser::detectAtToken(int length, bool hasEscape)
                 return;
 
 #if ENABLE(CSS_REGIONS)
-            if (isASCIIAlphaCaselessEqual(name[14], 'n') && isEqualToCSSIdentifier(name + 2, "webkit-regio")) {
+            if (isASCIIAlphaCaselessEqual(name[14], 'n') && isEqualToCSSIdentifier(name + 2, "webkit-regio"))
                 m_token = WEBKIT_REGION_RULE_SYM;
-                return;
-            }
-#endif
-#if ENABLE(CSS_SHADERS)
-            if (isASCIIAlphaCaselessEqual(name[14], 'r') && isEqualToCSSIdentifier(name + 2, "webkit-filte")) {
-                m_token = WEBKIT_FILTER_RULE_SYM;
-                return;
-            }
 #endif
             return;
 
@@ -10816,7 +12269,9 @@ inline void CSSParser::detectAtToken(int length, bool hasEscape)
 
         case 18:
             if (isEqualToCSSIdentifier(name + 2, "webkit-keyframes"))
-                m_token = WEBKIT_KEYFRAMES_SYM;
+                m_token = KEYFRAMES_SYM;
+            else if (isEqualToCSSIdentifier(name + 2, "webkit-sizesattr"))
+                m_token = WEBKIT_SIZESATTR_SYM;
             return;
 
         case 19:
@@ -10828,22 +12283,19 @@ inline void CSSParser::detectAtToken(int length, bool hasEscape)
 
         case 22:
             if (!hasEscape && isEqualToCSSIdentifier(name + 2, "webkit-keyframe-rule"))
-                m_token = WEBKIT_KEYFRAME_RULE_SYM;
+                m_token = KEYFRAME_RULE_SYM;
             return;
 
         case 27:
-#if ENABLE(CSS3_CONDITIONAL_RULES)
             if (isEqualToCSSIdentifier(name + 2, "webkit-supports-condition")) {
                 m_parsingMode = SupportsMode;
                 m_token = WEBKIT_SUPPORTS_CONDITION_SYM;
             }
-#endif
             return;
         }
     }
 }
 
-#if ENABLE(CSS3_CONDITIONAL_RULES)
 template <typename CharacterType>
 inline void CSSParser::detectSupportsToken(int length)
 {
@@ -10860,7 +12312,6 @@ inline void CSSParser::detectSupportsToken(int length)
             m_token = SUPPORTS_NOT;
     }
 }
-#endif
 
 template <typename SrcCharacterType>
 int CSSParser::realLex(void* yylvalWithoutType)
@@ -10882,18 +12333,20 @@ restartAfterComment:
     result = currentCharacter<SrcCharacterType>();
     setTokenStart(result);
     m_tokenStartLineNumber = m_lineNumber;
+    m_tokenStartColumnNumber = tokenStartOffset() - m_columnOffsetForLine;
     m_token = *currentCharacter<SrcCharacterType>();
     ++currentCharacter<SrcCharacterType>();
 
     switch ((m_token <= 127) ? typesOfASCIICharacters[m_token] : CharacterIdentifierStart) {
     case CharacterCaselessU:
-        if (UNLIKELY(*currentCharacter<SrcCharacterType>() == '+'))
+        if (UNLIKELY(*currentCharacter<SrcCharacterType>() == '+')) {
             if (parseUnicodeRange<SrcCharacterType>()) {
                 m_token = UNICODERANGE;
                 yylval->string.init(tokenStart<SrcCharacterType>(), currentCharacter<SrcCharacterType>() - tokenStart<SrcCharacterType>());
                 break;
             }
-        // Fall through to CharacterIdentifierStart.
+        }
+        FALLTHROUGH; // To CharacterIdentifierStart.
 
     case CharacterIdentifierStart:
         --currentCharacter<SrcCharacterType>();
@@ -10901,13 +12354,11 @@ restartAfterComment:
         m_token = IDENT;
 
         if (UNLIKELY(*currentCharacter<SrcCharacterType>() == '(')) {
-#if ENABLE(CSS3_CONDITIONAL_RULES)
             if (m_parsingMode == SupportsMode && !hasEscape) {
                 detectSupportsToken<SrcCharacterType>(result - tokenStart<SrcCharacterType>());
                 if (m_token != IDENT)
                     break;
             }
-#endif
             m_token = FUNCTION;
             bool shouldSkipParenthesis = true;
             if (!hasEscape) {
@@ -10937,10 +12388,8 @@ restartAfterComment:
         } else if (UNLIKELY(m_parsingMode != NormalMode) && !hasEscape) {
             if (m_parsingMode == MediaQueryMode)
                 detectMediaQueryToken<SrcCharacterType>(result - tokenStart<SrcCharacterType>());
-#if ENABLE(CSS3_CONDITIONAL_RULES)
             else if (m_parsingMode == SupportsMode)
                 detectSupportsToken<SrcCharacterType>(result - tokenStart<SrcCharacterType>());
-#endif
             else if (m_parsingMode == NthChildMode && isASCIIAlphaCaselessEqual(tokenStart<SrcCharacterType>()[0], 'n')) {
                 if (result - tokenStart<SrcCharacterType>() == 1) {
                     // String "n" is IDENT but "n+1" is NTH.
@@ -10963,12 +12412,16 @@ restartAfterComment:
                 }
             }
         }
+        if (m_parsingMode == NthChildMode && m_token == IDENT && yylval->string.length() == 2 && equalLettersIgnoringASCIICase(yylval->string, "of")) {
+            m_parsingMode = NormalMode;
+            m_token = NTHCHILDSELECTORSEPARATOR;
+        }
         break;
 
     case CharacterDot:
         if (!isASCIIDigit(currentCharacter<SrcCharacterType>()[0]))
             break;
-        // Fall through to CharacterNumber.
+        FALLTHROUGH; // To CharacterNumber.
 
     case CharacterNumber: {
         bool dotSeen = (m_token == '.');
@@ -10993,7 +12446,6 @@ restartAfterComment:
             break;
         }
 
-#if ENABLE(SVG)
         // Use SVG parser for numbers on SVG presentation attributes.
         if (m_context.mode == SVGAttributeMode) {
             // We need to take care of units like 'em' or 'ex'.
@@ -11013,7 +12465,6 @@ restartAfterComment:
             if (!parseSVGNumber(tokenStart<SrcCharacterType>(), character - tokenStart<SrcCharacterType>(), yylval->number))
                 break;
         } else
-#endif
             yylval->number = charactersToDouble(tokenStart<SrcCharacterType>(), currentCharacter<SrcCharacterType>() - tokenStart<SrcCharacterType>());
  
         // Type of the function.
@@ -11049,11 +12500,6 @@ restartAfterComment:
             parseIdentifier(result, resultString, hasEscape);
             m_token = IDENT;
 
-#if ENABLE(CSS_VARIABLES)
-            if (cssVariablesEnabled() && isEqualToCSSCaseSensitiveIdentifier(tokenStart<SrcCharacterType>() + 1, "webkit-var") && tokenStart<SrcCharacterType>()[11] == '-' && isIdentifierStartAfterDash(tokenStart<SrcCharacterType>() + 12))
-                m_token = VAR_DEFINITION;
-            else
-#endif
             if (*currentCharacter<SrcCharacterType>() == '(') {
                 m_token = FUNCTION;
                 if (!hasEscape)
@@ -11086,6 +12532,11 @@ restartAfterComment:
         } else if (currentCharacter<SrcCharacterType>()[0] == '-' && currentCharacter<SrcCharacterType>()[1] == '>') {
             currentCharacter<SrcCharacterType>() += 2;
             m_token = SGML_CD;
+        } else if (currentCharacter<SrcCharacterType>()[0] == '-') {
+            --currentCharacter<SrcCharacterType>();
+            parseIdentifier(result, resultString, hasEscape);
+            m_token = CUSTOM_PROPERTY;
+            yylval->string = resultString;
         } else if (UNLIKELY(m_parsingMode == NthChildMode)) {
             // "-[0-9]+n" is always an NthChild.
             if (parseNthChild<SrcCharacterType>()) {
@@ -11110,16 +12561,20 @@ restartAfterComment:
         // Might start with a '\n'.
         --currentCharacter<SrcCharacterType>();
         do {
-            if (*currentCharacter<SrcCharacterType>() == '\n')
+            if (*currentCharacter<SrcCharacterType>() == '\n') {
                 ++m_lineNumber;
+                m_columnOffsetForLine = currentCharacterOffset() + 1;
+            }
             ++currentCharacter<SrcCharacterType>();
         } while (*currentCharacter<SrcCharacterType>() <= ' ' && (typesOfASCIICharacters[*currentCharacter<SrcCharacterType>()] == CharacterWhiteSpace));
         break;
 
-    case CharacterEndMediaQuery:
-        if (m_parsingMode == MediaQueryMode)
+    case CharacterEndConditionQuery: {
+        bool isParsingCondition = m_parsingMode == MediaQueryMode || m_parsingMode == SupportsMode;
+        if (isParsingCondition)
             m_parsingMode = NormalMode;
         break;
+    }
 
     case CharacterEndNthChild:
         if (m_parsingMode == NthChildMode)
@@ -11178,9 +12633,10 @@ restartAfterComment:
         if (*currentCharacter<SrcCharacterType>() == '*') {
             ++currentCharacter<SrcCharacterType>();
             while (currentCharacter<SrcCharacterType>()[0] != '*' || currentCharacter<SrcCharacterType>()[1] != '/') {
-                if (*currentCharacter<SrcCharacterType>() == '\n')
+                if (*currentCharacter<SrcCharacterType>() == '\n') {
                     ++m_lineNumber;
-                if (*currentCharacter<SrcCharacterType>() == '\0') {
+                    m_columnOffsetForLine = currentCharacterOffset() + 1;
+                } else if (*currentCharacter<SrcCharacterType>() == '\0') {
                     // Unterminated comments are simply ignored.
                     currentCharacter<SrcCharacterType>() -= 2;
                     break;
@@ -11239,6 +12695,10 @@ restartAfterComment:
             parseIdentifier(result, yylval->string, hasEscape);
             m_token = IDENT;
         }
+        if (m_parsingMode == NthChildMode && m_token == IDENT && yylval->string.length() == 2 && equalLettersIgnoringASCIICase(yylval->string, "of")) {
+            m_parsingMode = NormalMode;
+            m_token = NTHCHILDSELECTORSEPARATOR;
+        }
         break;
 
     case CharacterXor:
@@ -11270,161 +12730,18 @@ restartAfterComment:
     return token();
 }
 
-CSSParserSelector* CSSParser::createFloatingSelectorWithTagName(const QualifiedName& tagQName)
-{
-    CSSParserSelector* selector = new CSSParserSelector(tagQName);
-    m_floatingSelectors.add(selector);
-    return selector;
-}
-
-CSSParserSelector* CSSParser::createFloatingSelector()
-{
-    CSSParserSelector* selector = new CSSParserSelector;
-    m_floatingSelectors.add(selector);
-    return selector;
-}
-
-PassOwnPtr<CSSParserSelector> CSSParser::sinkFloatingSelector(CSSParserSelector* selector)
-{
-    if (selector) {
-        ASSERT(m_floatingSelectors.contains(selector));
-        m_floatingSelectors.remove(selector);
-    }
-    return adoptPtr(selector);
-}
-
-Vector<OwnPtr<CSSParserSelector> >* CSSParser::createFloatingSelectorVector()
-{
-    Vector<OwnPtr<CSSParserSelector> >* selectorVector = new Vector<OwnPtr<CSSParserSelector> >;
-    m_floatingSelectorVectors.add(selectorVector);
-    return selectorVector;
-}
-
-PassOwnPtr<Vector<OwnPtr<CSSParserSelector> > > CSSParser::sinkFloatingSelectorVector(Vector<OwnPtr<CSSParserSelector> >* selectorVector)
-{
-    if (selectorVector) {
-        ASSERT(m_floatingSelectorVectors.contains(selectorVector));
-        m_floatingSelectorVectors.remove(selectorVector);
-    }
-    return adoptPtr(selectorVector);
-}
-
-CSSParserValueList* CSSParser::createFloatingValueList()
-{
-    CSSParserValueList* list = new CSSParserValueList;
-    m_floatingValueLists.add(list);
-    return list;
-}
-
-PassOwnPtr<CSSParserValueList> CSSParser::sinkFloatingValueList(CSSParserValueList* list)
-{
-    if (list) {
-        ASSERT(m_floatingValueLists.contains(list));
-        m_floatingValueLists.remove(list);
-    }
-    return adoptPtr(list);
-}
-
-CSSParserFunction* CSSParser::createFloatingFunction()
-{
-    CSSParserFunction* function = new CSSParserFunction;
-    m_floatingFunctions.add(function);
-    return function;
-}
-
-PassOwnPtr<CSSParserFunction> CSSParser::sinkFloatingFunction(CSSParserFunction* function)
-{
-    if (function) {
-        ASSERT(m_floatingFunctions.contains(function));
-        m_floatingFunctions.remove(function);
-    }
-    return adoptPtr(function);
-}
-
-CSSParserValue& CSSParser::sinkFloatingValue(CSSParserValue& value)
-{
-    if (value.unit == CSSParserValue::Function) {
-        ASSERT(m_floatingFunctions.contains(value.function));
-        m_floatingFunctions.remove(value.function);
-    }
-    return value;
-}
-
-MediaQueryExp* CSSParser::createFloatingMediaQueryExp(const AtomicString& mediaFeature, CSSParserValueList* values)
-{
-    m_floatingMediaQueryExp = MediaQueryExp::create(mediaFeature, values);
-    return m_floatingMediaQueryExp.get();
-}
-
-PassOwnPtr<MediaQueryExp> CSSParser::sinkFloatingMediaQueryExp(MediaQueryExp* expression)
-{
-    ASSERT_UNUSED(expression, expression == m_floatingMediaQueryExp);
-    return m_floatingMediaQueryExp.release();
-}
-
-Vector<OwnPtr<MediaQueryExp> >* CSSParser::createFloatingMediaQueryExpList()
-{
-    m_floatingMediaQueryExpList = adoptPtr(new Vector<OwnPtr<MediaQueryExp> >);
-    return m_floatingMediaQueryExpList.get();
-}
-
-PassOwnPtr<Vector<OwnPtr<MediaQueryExp> > > CSSParser::sinkFloatingMediaQueryExpList(Vector<OwnPtr<MediaQueryExp> >* list)
-{
-    ASSERT_UNUSED(list, list == m_floatingMediaQueryExpList);
-    return m_floatingMediaQueryExpList.release();
-}
-
-MediaQuery* CSSParser::createFloatingMediaQuery(MediaQuery::Restrictor restrictor, const String& mediaType, PassOwnPtr<Vector<OwnPtr<MediaQueryExp> > > expressions)
-{
-    m_floatingMediaQuery = adoptPtr(new MediaQuery(restrictor, mediaType, expressions));
-    return m_floatingMediaQuery.get();
-}
-
-MediaQuery* CSSParser::createFloatingMediaQuery(PassOwnPtr<Vector<OwnPtr<MediaQueryExp> > > expressions)
-{
-    return createFloatingMediaQuery(MediaQuery::None, "all", expressions);
-}
-
-PassOwnPtr<MediaQuery> CSSParser::sinkFloatingMediaQuery(MediaQuery* query)
-{
-    ASSERT_UNUSED(query, query == m_floatingMediaQuery);
-    return m_floatingMediaQuery.release();
-}
-
-Vector<RefPtr<StyleKeyframe> >* CSSParser::createFloatingKeyframeVector()
-{
-    m_floatingKeyframeVector = adoptPtr(new Vector<RefPtr<StyleKeyframe> >());
-    return m_floatingKeyframeVector.get();
-}
-
-PassOwnPtr<Vector<RefPtr<StyleKeyframe> > > CSSParser::sinkFloatingKeyframeVector(Vector<RefPtr<StyleKeyframe> >* keyframeVector)
-{
-    ASSERT_UNUSED(keyframeVector, m_floatingKeyframeVector == keyframeVector);
-    return m_floatingKeyframeVector.release();
-}
-
-MediaQuerySet* CSSParser::createMediaQuerySet()
-{
-    RefPtr<MediaQuerySet> queries = MediaQuerySet::create();
-    MediaQuerySet* result = queries.get();
-    m_parsedMediaQuerySets.append(queries.release());
-    return result;
-}
-
-StyleRuleBase* CSSParser::createImportRule(const CSSParserString& url, MediaQuerySet* media)
+RefPtr<StyleRuleBase> CSSParser::createImportRule(const CSSParserString& url, PassRefPtr<MediaQuerySet> media)
 {
     if (!media || !m_allowImportRules) {
         popRuleData();
-        return 0;
+        return nullptr;
     }
     RefPtr<StyleRuleImport> rule = StyleRuleImport::create(url, media);
-    StyleRuleImport* result = rule.get();
-    m_parsedRules.append(rule.release());
     processAndAddNewRuleToSourceTreeIfNeeded();
-    return result;
+    return rule;
 }
 
-StyleRuleBase* CSSParser::createMediaRule(MediaQuerySet* media, RuleList* rules)
+RefPtr<StyleRuleBase> CSSParser::createMediaRule(PassRefPtr<MediaQuerySet> media, RuleList* rules)
 {
     m_allowImportRules = m_allowNamespaceDeclarations = false;
     RefPtr<StyleRuleMedia> rule;
@@ -11435,19 +12752,16 @@ StyleRuleBase* CSSParser::createMediaRule(MediaQuerySet* media, RuleList* rules)
         rule = StyleRuleMedia::create(MediaQuerySet::create(), emptyRules);
     } else
         rule = StyleRuleMedia::create(media, rules ? *rules : emptyRules);
-    StyleRuleMedia* result = rule.get();
-    m_parsedRules.append(rule.release());
     processAndAddNewRuleToSourceTreeIfNeeded();
-    return result;
+    return rule;
 }
 
-StyleRuleBase* CSSParser::createEmptyMediaRule(RuleList* rules)
+RefPtr<StyleRuleBase> CSSParser::createEmptyMediaRule(RuleList* rules)
 {
-    return createMediaRule(MediaQuerySet::create().get(), rules);
+    return createMediaRule(MediaQuerySet::create(), rules);
 }
 
-#if ENABLE(CSS3_CONDITIONAL_RULES)
-StyleRuleBase* CSSParser::createSupportsRule(bool conditionIsSupported, RuleList* rules)
+RefPtr<StyleRuleBase> CSSParser::createSupportsRule(bool conditionIsSupported, RuleList* rules)
 {
     m_allowImportRules = m_allowNamespaceDeclarations = false;
 
@@ -11469,17 +12783,15 @@ StyleRuleBase* CSSParser::createSupportsRule(bool conditionIsSupported, RuleList
         rule = StyleRuleSupports::create(conditionText, conditionIsSupported, emptyRules);
     }
 
-    StyleRuleSupports* result = rule.get();
-    m_parsedRules.append(rule.release());
     processAndAddNewRuleToSourceTreeIfNeeded();
 
-    return result;
+    return rule;
 }
 
 void CSSParser::markSupportsRuleHeaderStart()
 {
     if (!m_supportsRuleDataStack)
-        m_supportsRuleDataStack = adoptPtr(new RuleSourceDataList());
+        m_supportsRuleDataStack = std::make_unique<RuleSourceDataList>();
 
     RefPtr<CSSRuleSourceData> data = CSSRuleSourceData::create(CSSRuleSourceData::SUPPORTS_RULE);
     data->ruleHeaderRange.start = tokenStartOffset();
@@ -11496,23 +12808,12 @@ void CSSParser::markSupportsRuleHeaderEnd()
         m_supportsRuleDataStack->last()->ruleHeaderRange.end = tokenStart<UChar>() - m_dataStart16.get();
 }
 
-PassRefPtr<CSSRuleSourceData> CSSParser::popSupportsRuleData()
+RefPtr<CSSRuleSourceData> CSSParser::popSupportsRuleData()
 {
     ASSERT(m_supportsRuleDataStack && !m_supportsRuleDataStack->isEmpty());
     RefPtr<CSSRuleSourceData> data = m_supportsRuleDataStack->last();
     m_supportsRuleDataStack->removeLast();
-    return data.release();
-}
-
-#endif
-
-CSSParser::RuleList* CSSParser::createRuleList()
-{
-    OwnPtr<RuleList> list = adoptPtr(new RuleList);
-    RuleList* listPtr = list.get();
-
-    m_parsedRuleLists.append(list.release());
-    return listPtr;
+    return data;
 }
 
 void CSSParser::processAndAddNewRuleToSourceTreeIfNeeded()
@@ -11539,10 +12840,10 @@ void CSSParser::addNewRuleToSourceTree(PassRefPtr<CSSRuleSourceData> rule)
 PassRefPtr<CSSRuleSourceData> CSSParser::popRuleData()
 {
     if (!m_ruleSourceDataResult)
-        return 0;
+        return nullptr;
 
     ASSERT(!m_currentRuleDataStack->isEmpty());
-    m_currentRuleData.clear();
+    m_currentRuleData = nullptr;
     RefPtr<CSSRuleSourceData> data = m_currentRuleDataStack->last();
     m_currentRuleDataStack->removeLast();
     return data.release();
@@ -11552,14 +12853,15 @@ void CSSParser::syntaxError(const Location& location, SyntaxErrorType error)
 {
     if (!isLoggingErrors())
         return;
+
     StringBuilder builder;
     switch (error) {
     case PropertyDeclarationError:
         builder.appendLiteral("Invalid CSS property declaration at: ");
         break;
-
     default:
         builder.appendLiteral("Unexpected CSS token: ");
+        break;
     }
 
     if (location.token.is8Bit())
@@ -11567,7 +12869,7 @@ void CSSParser::syntaxError(const Location& location, SyntaxErrorType error)
     else
         builder.append(location.token.characters16(), location.token.length());
 
-    logError(builder.toString(), location.lineNumber);
+    logError(builder.toString(), location.lineNumber, location.columnNumber);
 
     m_ignoreErrorsInDeclaration = true;
 }
@@ -11577,89 +12879,59 @@ bool CSSParser::isLoggingErrors()
     return m_logErrors && !m_ignoreErrorsInDeclaration;
 }
 
-void CSSParser::logError(const String& message, int lineNumber)
+void CSSParser::logError(const String& message, int lineNumber, int columnNumber)
 {
-    // FIXME: <http://webkit.org/b/114313> CSS Parser ConsoleMessage errors should include column numbers
-    PageConsole* console = m_styleSheet->singleOwnerDocument()->page()->console();
-    console->addMessage(CSSMessageSource, WarningMessageLevel, message, m_styleSheet->baseURL().string(), lineNumber + 1, 0);
+    PageConsoleClient& console = m_styleSheet->singleOwnerDocument()->page()->console();
+    console.addMessage(MessageSource::CSS, MessageLevel::Warning, message, m_styleSheet->baseURL().string(), lineNumber + 1, columnNumber + 1);
 }
 
-StyleRuleKeyframes* CSSParser::createKeyframesRule(const String& name, PassOwnPtr<Vector<RefPtr<StyleKeyframe> > > popKeyframes)
+RefPtr<StyleRuleKeyframes> CSSParser::createKeyframesRule(const String& name, std::unique_ptr<Vector<RefPtr<StyleKeyframe>>> popKeyframes)
 {
-    OwnPtr<Vector<RefPtr<StyleKeyframe> > > keyframes = popKeyframes;
+    std::unique_ptr<Vector<RefPtr<StyleKeyframe>>> keyframes = WTFMove(popKeyframes);
     m_allowImportRules = m_allowNamespaceDeclarations = false;
     RefPtr<StyleRuleKeyframes> rule = StyleRuleKeyframes::create();
     for (size_t i = 0; i < keyframes->size(); ++i)
         rule->parserAppendKeyframe(keyframes->at(i));
     rule->setName(name);
-    StyleRuleKeyframes* rulePtr = rule.get();
-    m_parsedRules.append(rule.release());
     processAndAddNewRuleToSourceTreeIfNeeded();
-    return rulePtr;
+    return rule;
 }
 
-StyleRuleBase* CSSParser::createStyleRule(Vector<OwnPtr<CSSParserSelector> >* selectors)
+RefPtr<StyleRuleBase> CSSParser::createStyleRule(Vector<std::unique_ptr<CSSParserSelector>>* selectors)
 {
-    StyleRule* result = 0;
+    RefPtr<StyleRule> rule;
     if (selectors) {
-        m_allowImportRules = m_allowNamespaceDeclarations = false;
-        RefPtr<StyleRule> rule = StyleRule::create(m_lastSelectorLineNumber);
+        m_allowImportRules = false;
+        m_allowNamespaceDeclarations = false;
+        rule = StyleRule::create(m_lastSelectorLineNumber, createStyleProperties());
         rule->parserAdoptSelectorVector(*selectors);
-        if (m_hasFontFaceOnlyValues)
-            deleteFontFaceOnlyValues();
-        rule->setProperties(createStylePropertySet());
-        result = rule.get();
-        m_parsedRules.append(rule.release());
         processAndAddNewRuleToSourceTreeIfNeeded();
     } else
         popRuleData();
     clearProperties();
-    return result;
+    return rule;
 }
 
-StyleRuleBase* CSSParser::createFontFaceRule()
+RefPtr<StyleRuleBase> CSSParser::createFontFaceRule()
 {
     m_allowImportRules = m_allowNamespaceDeclarations = false;
     for (unsigned i = 0; i < m_parsedProperties.size(); ++i) {
         CSSProperty& property = m_parsedProperties[i];
-        if (property.id() == CSSPropertyFontVariant && property.value()->isPrimitiveValue())
-            property.wrapValueInCommaSeparatedList();
-        else if (property.id() == CSSPropertyFontFamily && (!property.value()->isValueList() || static_cast<CSSValueList*>(property.value())->length() != 1)) {
+        if (property.id() == CSSPropertyFontFamily && (!is<CSSValueList>(*property.value()) || downcast<CSSValueList>(*property.value()).length() != 1)) {
             // Unlike font-family property, font-family descriptor in @font-face rule
             // has to be a value list with exactly one family name. It cannot have a
             // have 'initial' value and cannot 'inherit' from parent.
             // See http://dev.w3.org/csswg/css3-fonts/#font-family-desc
             clearProperties();
             popRuleData();
-            return 0;
+            return nullptr;
         }
     }
-    RefPtr<StyleRuleFontFace> rule = StyleRuleFontFace::create();
-    rule->setProperties(createStylePropertySet());
+    RefPtr<StyleRuleFontFace> rule = StyleRuleFontFace::create(createStyleProperties());
     clearProperties();
-    StyleRuleFontFace* result = rule.get();
-    m_parsedRules.append(rule.release());
-    processAndAddNewRuleToSourceTreeIfNeeded();
-    return result;
-}
-
-#if ENABLE(SHADOW_DOM)
-StyleRuleBase* CSSParser::createHostRule(RuleList* rules)
-{
-    m_allowImportRules = m_allowNamespaceDeclarations = false;
-    RefPtr<StyleRuleHost> rule;
-    if (rules)
-        rule = StyleRuleHost::create(*rules);
-    else {
-        RuleList emptyRules;
-        rule = StyleRuleHost::create(emptyRules);
-    }
-    StyleRuleHost* result = rule.get();
-    m_parsedRules.append(rule.release());
     processAndAddNewRuleToSourceTreeIfNeeded();
-    return result;
+    return rule;
 }
-#endif
 
 void CSSParser::addNamespace(const AtomicString& prefix, const AtomicString& uri)
 {
@@ -11678,30 +12950,27 @@ QualifiedName CSSParser::determineNameInNamespace(const AtomicString& prefix, co
     return QualifiedName(prefix, localName, m_styleSheet->determineNamespace(prefix));
 }
 
-CSSParserSelector* CSSParser::rewriteSpecifiersWithNamespaceIfNeeded(CSSParserSelector* specifiers)
+void CSSParser::rewriteSpecifiersWithNamespaceIfNeeded(CSSParserSelector& specifiers)
 {
-    if (m_defaultNamespace != starAtom || specifiers->isCustomPseudoElement())
-        return rewriteSpecifiersWithElementName(nullAtom, starAtom, specifiers, /*tagIsForNamespaceRule*/true);
-    return specifiers;
+    if (m_defaultNamespace != starAtom || specifiers.isCustomPseudoElement())
+        rewriteSpecifiersWithElementName(nullAtom, starAtom, specifiers, /*tagIsForNamespaceRule*/true);
 }
 
-CSSParserSelector* CSSParser::rewriteSpecifiersWithElementName(const AtomicString& namespacePrefix, const AtomicString& elementName, CSSParserSelector* specifiers, bool tagIsForNamespaceRule)
+void CSSParser::rewriteSpecifiersWithElementName(const AtomicString& namespacePrefix, const AtomicString& elementName, CSSParserSelector& specifiers, bool tagIsForNamespaceRule)
 {
     AtomicString determinedNamespace = namespacePrefix != nullAtom && m_styleSheet ? m_styleSheet->determineNamespace(namespacePrefix) : m_defaultNamespace;
     QualifiedName tag(namespacePrefix, elementName, determinedNamespace);
 
-    if (!specifiers->isCustomPseudoElement()) {
+    if (!specifiers.isCustomPseudoElement()) {
         if (tag == anyQName())
-            return specifiers;
-#if ENABLE(VIDEO_TRACK)
-        if (!(specifiers->pseudoType() == CSSSelector::PseudoCue))
-#endif
-            specifiers->prependTagSelector(tag, tagIsForNamespaceRule);
-        return specifiers;
+            return;
+        if (!specifiers.isPseudoElementCueFunction())
+            specifiers.prependTagSelector(tag, tagIsForNamespaceRule);
+        return;
     }
 
-    CSSParserSelector* lastShadowDescendant = specifiers;
-    CSSParserSelector* history = specifiers;
+    CSSParserSelector* lastShadowDescendant = &specifiers;
+    CSSParserSelector* history = &specifiers;
     while (history->tagHistory()) {
         history = history->tagHistory();
         if (history->isCustomPseudoElement() || history->hasShadowDescendant())
@@ -11711,83 +12980,81 @@ CSSParserSelector* CSSParser::rewriteSpecifiersWithElementName(const AtomicStrin
     if (lastShadowDescendant->tagHistory()) {
         if (tag != anyQName())
             lastShadowDescendant->tagHistory()->prependTagSelector(tag, tagIsForNamespaceRule);
-        return specifiers;
+        return;
     }
 
     // For shadow-ID pseudo-elements to be correctly matched, the ShadowDescendant combinator has to be used.
     // We therefore create a new Selector with that combinator here in any case, even if matching any (host) element in any namespace (i.e. '*').
-    OwnPtr<CSSParserSelector> elementNameSelector = adoptPtr(new CSSParserSelector(tag));
-    lastShadowDescendant->setTagHistory(elementNameSelector.release());
+    lastShadowDescendant->setTagHistory(std::make_unique<CSSParserSelector>(tag));
     lastShadowDescendant->setRelation(CSSSelector::ShadowDescendant);
-    return specifiers;
 }
 
-CSSParserSelector* CSSParser::rewriteSpecifiers(CSSParserSelector* specifiers, CSSParserSelector* newSpecifier)
+std::unique_ptr<CSSParserSelector> CSSParser::rewriteSpecifiers(std::unique_ptr<CSSParserSelector> specifiers, std::unique_ptr<CSSParserSelector> newSpecifier)
 {
-#if ENABLE(VIDEO_TRACK)
-    if (newSpecifier->isCustomPseudoElement() || newSpecifier->pseudoType() == CSSSelector::PseudoCue) {
-#else
-    if (newSpecifier->isCustomPseudoElement()) {
-#endif
+    if (newSpecifier->isCustomPseudoElement() || newSpecifier->isPseudoElementCueFunction()) {
         // Unknown pseudo element always goes at the top of selector chain.
-        newSpecifier->appendTagHistory(CSSSelector::ShadowDescendant, sinkFloatingSelector(specifiers));
+        newSpecifier->appendTagHistory(CSSSelector::ShadowDescendant, WTFMove(specifiers));
         return newSpecifier;
     }
     if (specifiers->isCustomPseudoElement()) {
         // Specifiers for unknown pseudo element go right behind it in the chain.
-        specifiers->insertTagHistory(CSSSelector::SubSelector, sinkFloatingSelector(newSpecifier), CSSSelector::ShadowDescendant);
+        specifiers->insertTagHistory(CSSSelector::SubSelector, WTFMove(newSpecifier), CSSSelector::ShadowDescendant);
         return specifiers;
     }
-    specifiers->appendTagHistory(CSSSelector::SubSelector, sinkFloatingSelector(newSpecifier));
+    specifiers->appendTagHistory(CSSSelector::SubSelector, WTFMove(newSpecifier));
     return specifiers;
 }
 
-StyleRuleBase* CSSParser::createPageRule(PassOwnPtr<CSSParserSelector> pageSelector)
+RefPtr<StyleRuleBase> CSSParser::createPageRule(std::unique_ptr<CSSParserSelector> pageSelector)
 {
     // FIXME: Margin at-rules are ignored.
     m_allowImportRules = m_allowNamespaceDeclarations = false;
-    StyleRulePage* pageRule = 0;
+    RefPtr<StyleRulePage> rule;
     if (pageSelector) {
-        RefPtr<StyleRulePage> rule = StyleRulePage::create();
-        Vector<OwnPtr<CSSParserSelector> > selectorVector;
-        selectorVector.append(pageSelector);
+        rule = StyleRulePage::create(createStyleProperties());
+        Vector<std::unique_ptr<CSSParserSelector>> selectorVector;
+        selectorVector.append(WTFMove(pageSelector));
         rule->parserAdoptSelectorVector(selectorVector);
-        rule->setProperties(createStylePropertySet());
-        pageRule = rule.get();
-        m_parsedRules.append(rule.release());
         processAndAddNewRuleToSourceTreeIfNeeded();
     } else
         popRuleData();
     clearProperties();
-    return pageRule;
+    return rule;
 }
 
-void CSSParser::setReusableRegionSelectorVector(Vector<OwnPtr<CSSParserSelector> >* selectors)
+std::unique_ptr<Vector<std::unique_ptr<CSSParserSelector>>> CSSParser::createSelectorVector()
 {
-    if (selectors)
-        m_reusableRegionSelectorVector.swap(*selectors);
+    if (m_recycledSelectorVector) {
+        m_recycledSelectorVector->shrink(0);
+        return WTFMove(m_recycledSelectorVector);
+    }
+    return std::make_unique<Vector<std::unique_ptr<CSSParserSelector>>>();
 }
 
-StyleRuleBase* CSSParser::createRegionRule(Vector<OwnPtr<CSSParserSelector> >* regionSelector, RuleList* rules)
+void CSSParser::recycleSelectorVector(std::unique_ptr<Vector<std::unique_ptr<CSSParserSelector>>> vector)
+{
+    if (vector && !m_recycledSelectorVector)
+        m_recycledSelectorVector = WTFMove(vector);
+}
+
+RefPtr<StyleRuleBase> CSSParser::createRegionRule(Vector<std::unique_ptr<CSSParserSelector>>* regionSelector, RuleList* rules)
 {
     if (!cssRegionsEnabled() || !regionSelector || !rules) {
         popRuleData();
-        return 0;
+        return nullptr;
     }
 
     m_allowImportRules = m_allowNamespaceDeclarations = false;
 
     RefPtr<StyleRuleRegion> regionRule = StyleRuleRegion::create(regionSelector, *rules);
 
-    StyleRuleRegion* result = regionRule.get();
-    m_parsedRules.append(regionRule.release());
     if (isExtractingSourceData())
         addNewRuleToSourceTree(CSSRuleSourceData::createUnknown());
 
-    return result;
+    return regionRule;
 }
 
-StyleRuleBase* CSSParser::createMarginAtRule(CSSSelector::MarginBoxType /* marginBox */)
+void CSSParser::createMarginAtRule(CSSSelector::MarginBoxType /* marginBox */)
 {
     // FIXME: Implement margin at-rule here, using:
     //        - marginBox: margin box
@@ -11795,7 +13062,6 @@ StyleRuleBase* CSSParser::createMarginAtRule(CSSSelector::MarginBoxType /* margi
     // Don't forget to also update the action for page symbol in CSSGrammar.y such that margin at-rule data is cleared if page_selector is invalid.
 
     endDeclarationsForMarginBox();
-    return 0; // until this method is implemented.
 }
 
 void CSSParser::startDeclarationsForMarginBox()
@@ -11809,56 +13075,40 @@ void CSSParser::endDeclarationsForMarginBox()
     m_numParsedPropertiesBeforeMarginBox = INVALID_NUM_PARSED_PROPERTIES;
 }
 
-void CSSParser::deleteFontFaceOnlyValues()
-{
-    ASSERT(m_hasFontFaceOnlyValues);
-    for (unsigned i = 0; i < m_parsedProperties.size();) {
-        CSSProperty& property = m_parsedProperties[i];
-        if (property.id() == CSSPropertyFontVariant && property.value()->isValueList()) {
-            m_parsedProperties.remove(i);
-            continue;
-        }
-        ++i;
-    }
-}
-
-StyleKeyframe* CSSParser::createKeyframe(CSSParserValueList* keys)
+RefPtr<StyleKeyframe> CSSParser::createKeyframe(CSSParserValueList& keys)
 {
     // Create a key string from the passed keys
     StringBuilder keyString;
-    for (unsigned i = 0; i < keys->size(); ++i) {
+    for (unsigned i = 0; i < keys.size(); ++i) {
         // Just as per the comment below, we ignore keyframes with
         // invalid key values (plain numbers or unknown identifiers)
         // marked as CSSPrimitiveValue::CSS_UNKNOWN during parsing.
-        if (keys->valueAt(i)->unit == CSSPrimitiveValue::CSS_UNKNOWN) {
+        if (keys.valueAt(i)->unit == CSSPrimitiveValue::CSS_UNKNOWN) {
             clearProperties();
-            return 0;
+            return nullptr;
         }
 
-        ASSERT(keys->valueAt(i)->unit == CSSPrimitiveValue::CSS_NUMBER);
-        float key = static_cast<float>(keys->valueAt(i)->fValue);
+        ASSERT(keys.valueAt(i)->unit == CSSPrimitiveValue::CSS_NUMBER);
+        float key = static_cast<float>(keys.valueAt(i)->fValue);
         if (key < 0 || key > 100) {
             // As per http://www.w3.org/TR/css3-animations/#keyframes,
             // "If a keyframe selector specifies negative percentage values
             // or values higher than 100%, then the keyframe will be ignored."
             clearProperties();
-            return 0;
+            return nullptr;
         }
         if (i != 0)
             keyString.append(',');
-        keyString.append(String::number(key));
+        keyString.appendNumber(key);
         keyString.append('%');
     }
 
-    RefPtr<StyleKeyframe> keyframe = StyleKeyframe::create();
+    RefPtr<StyleKeyframe> keyframe = StyleKeyframe::create(createStyleProperties());
     keyframe->setKeyText(keyString.toString());
-    keyframe->setProperties(createStylePropertySet());
 
     clearProperties();
 
-    StyleKeyframe* keyframePtr = keyframe.get();
-    m_parsedKeyframes.append(keyframe.release());
-    return keyframePtr;
+    return keyframe;
 }
 
 void CSSParser::invalidBlockHit()
@@ -11978,7 +13228,7 @@ void CSSParser::markRuleHeaderEnd()
 
 void CSSParser::markSelectorStart()
 {
-    if (!isExtractingSourceData())
+    if (!isExtractingSourceData() || m_nestedSelectorLevel)
         return;
     ASSERT(!m_selectorRange.end);
 
@@ -11987,7 +13237,7 @@ void CSSParser::markSelectorStart()
 
 void CSSParser::markSelectorEnd()
 {
-    if (!isExtractingSourceData())
+    if (!isExtractingSourceData() || m_nestedSelectorLevel)
         return;
     ASSERT(!m_selectorRange.end);
     ASSERT(m_currentRuleDataStack->size());
@@ -12002,7 +13252,7 @@ void CSSParser::markRuleBodyStart()
 {
     if (!isExtractingSourceData())
         return;
-    m_currentRuleData.clear();
+    m_currentRuleData = nullptr;
     unsigned offset = tokenStartOffset();
     if (tokenStartChar() == '{')
         ++offset; // Skip the rule body opening brace.
@@ -12044,7 +13294,7 @@ void CSSParser::markPropertyEnd(bool isImportantFound, bool isPropertyParsed)
         // This stuff is only executed when the style data retrieval is requested by client.
         const unsigned start = m_propertyRange.start;
         const unsigned end = m_propertyRange.end;
-        ASSERT(start < end);
+        ASSERT_WITH_SECURITY_IMPLICATION(start < end);
         String propertyString;
         if (is8BitSource())
             propertyString = String(m_dataStart8.get() + start, end - start).stripWhiteSpace();
@@ -12066,29 +13316,26 @@ void CSSParser::markPropertyEnd(bool isImportantFound, bool isPropertyParsed)
 }
 
 #if ENABLE(CSS_DEVICE_ADAPTATION)
-StyleRuleBase* CSSParser::createViewportRule()
+PassRefPtr<StyleRuleBase> CSSParser::createViewportRule()
 {
     m_allowImportRules = m_allowNamespaceDeclarations = false;
 
-    RefPtr<StyleRuleViewport> rule = StyleRuleViewport::create();
-
-    rule->setProperties(createStylePropertySet());
+    RefPtr<StyleRuleViewport> rule = StyleRuleViewport::create(createStyleProperties());
     clearProperties();
 
-    StyleRuleViewport* result = rule.get();
-    m_parsedRules.append(rule.release());
     processAndAddNewRuleToSourceTreeIfNeeded();
 
-    return result;
+    return rule.release();
 }
 
 bool CSSParser::parseViewportProperty(CSSPropertyID propId, bool important)
 {
-    CSSParserValue* value = m_valueList->current();
-    if (!value)
+    if (!m_valueList->current())
         return false;
 
-    CSSValueID id = value->id;
+    ValueWithCalculation valueWithCalculation(*m_valueList->current());
+
+    CSSValueID id = valueWithCalculation.value().id;
     bool validPrimitive = false;
 
     switch (propId) {
@@ -12099,7 +13346,7 @@ bool CSSParser::parseViewportProperty(CSSPropertyID propId, bool important)
         if (id == CSSValueAuto || id == CSSValueDeviceWidth || id == CSSValueDeviceHeight)
             validPrimitive = true;
         else
-            validPrimitive = (!id && validUnit(value, FLength | FPercent | FNonNeg));
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FLength | FPercent | FNonNeg));
         break;
     case CSSPropertyWidth: // shorthand
         return parseViewportShorthand(propId, CSSPropertyMinWidth, CSSPropertyMaxWidth, important);
@@ -12111,7 +13358,7 @@ bool CSSParser::parseViewportProperty(CSSPropertyID propId, bool important)
         if (id == CSSValueAuto)
             validPrimitive = true;
         else
-            validPrimitive = (!id && validUnit(value, FNumber | FPercent | FNonNeg));
+            validPrimitive = (!id && validateUnit(valueWithCalculation, FNumber | FPercent | FNonNeg));
         break;
     case CSSPropertyUserZoom: // zoom | fixed
         if (id == CSSValueZoom || id == CSSValueFixed)
@@ -12126,7 +13373,7 @@ bool CSSParser::parseViewportProperty(CSSPropertyID propId, bool important)
 
     RefPtr<CSSValue> parsedValue;
     if (validPrimitive) {
-        parsedValue = parseValidPrimitive(id, value);
+        parsedValue = parseValidPrimitive(id, valueWithCalculation);
         m_valueList->next();
     }
 
@@ -12179,7 +13426,7 @@ static CSSPropertyID cssPropertyID(const CharacterType* propertyName, unsigned l
 #if ENABLE(LEGACY_CSS_VENDOR_PREFIXES)
         // If the prefix is -apple- or -khtml-, change it to -webkit-.
         // This makes the string one character longer.
-        if (RuntimeEnabledFeatures::legacyCSSVendorPrefixesEnabled()
+        if (RuntimeEnabledFeatures::sharedFeatures().legacyCSSVendorPrefixesEnabled()
             && (hasPrefix(buffer, length, "-apple-") || hasPrefix(buffer, length, "-khtml-"))) {
             memmove(buffer + 7, buffer + 6, length + 1 - 6);
             memcpy(buffer, "-webkit", 7);
@@ -12192,16 +13439,7 @@ static CSSPropertyID cssPropertyID(const CharacterType* propertyName, unsigned l
     }
 
     const Property* hashTableEntry = findProperty(name, length);
-    const CSSPropertyID propertyID = hashTableEntry ? static_cast<CSSPropertyID>(hashTableEntry->id) : CSSPropertyInvalid;
-
-    static const int cssPropertyHistogramSize = numCSSProperties;
-    if (hasPrefix(buffer, length, "-webkit-") && propertyID != CSSPropertyInvalid) {
-        int histogramValue = propertyID - firstCSSProperty;
-        ASSERT(0 <= histogramValue && histogramValue < cssPropertyHistogramSize);
-        HistogramSupport::histogramEnumeration("CSS.PrefixUsage", histogramValue, cssPropertyHistogramSize);
-    }
-
-    return propertyID;
+    return hashTableEntry ? static_cast<CSSPropertyID>(hashTableEntry->id) : CSSPropertyInvalid;
 }
 
 CSSPropertyID cssPropertyID(const String& string)
@@ -12240,6 +13478,17 @@ void cssPropertyNameIOSAliasing(const char* propertyName, const char*& propertyN
 }
 #endif
 
+static bool isAppleLegacyCssValueKeyword(const char* valueKeyword, unsigned length)
+{
+    static const char* applePrefix = "-apple-";
+    static const char* appleSystemPrefix = "-apple-system";
+    static const char* appleWirelessPlaybackTargetActive = getValueName(CSSValueAppleWirelessPlaybackTargetActive);
+
+    return hasPrefix(valueKeyword, length, applePrefix)
+        && !hasPrefix(valueKeyword, length, appleSystemPrefix)
+        && !WTF::equal(reinterpret_cast<const LChar*>(valueKeyword), reinterpret_cast<const LChar*>(appleWirelessPlaybackTargetActive), length);
+}
+
 template <typename CharacterType>
 static CSSValueID cssValueKeywordID(const CharacterType* valueKeyword, unsigned length)
 {
@@ -12256,7 +13505,9 @@ static CSSValueID cssValueKeywordID(const CharacterType* valueKeyword, unsigned
     if (buffer[0] == '-') {
         // If the prefix is -apple- or -khtml-, change it to -webkit-.
         // This makes the string one character longer.
-        if (hasPrefix(buffer, length, "-apple-") || hasPrefix(buffer, length, "-khtml-")) {
+        // On iOS we don't want to change values starting with -apple-system to -webkit-system.
+        // FIXME: Remove this mangling without breaking the web.
+        if (isAppleLegacyCssValueKeyword(buffer, length) || hasPrefix(buffer, length, "-khtml-")) {
             memmove(buffer + 7, buffer + 6, length + 1 - 6);
             memcpy(buffer, "-webkit", 7);
             ++length;
@@ -12439,8 +13690,10 @@ bool isValidNthToken(const CSSParserString& token)
     // However, since the {ident} rule precedes the {nth} rule, some of those
     // tokens are identified as string literal. Furthermore we need to accept
     // "odd" and "even" which does not match to an+b.
-    return equalIgnoringCase(token, "odd") || equalIgnoringCase(token, "even")
-        || equalIgnoringCase(token, "n") || equalIgnoringCase(token, "-n");
+    return equalLettersIgnoringASCIICase(token, "odd")
+        || equalLettersIgnoringASCIICase(token, "even")
+        || equalLettersIgnoringASCIICase(token, "n")
+        || equalLettersIgnoringASCIICase(token, "-n");
 }
 
 }