Merge remote-tracking branch 'origin/5.8' into dev

Change-Id: Ib2a1eb4dfae2fb5a98066d3d0f8f09f4e1d61d3f

34 files changed, 292 insertions, 125 deletions

diff --git a/src/core/api/core_api.pro b/src/core/api/core_api.pro
index cb9d33087..37f8885bb 100644
--- a/src/core/api/core_api.pro
+++ b/src/core/api/core_api.pro
@@ -15,9 +15,7 @@ CONFIG -= create_prl
 # Copy this logic from qt_module.prf so that the intermediate library can be
 # created to the same rules as the final module linking in core_module.pro.
 !host_build:if(win32|mac):!macx-xcode {
-    qtConfig(simulator_and_device): CONFIG += simulator_and_device
-    qtConfig(debug_and_release): CONFIG += debug_and_release
-    qtConfig(build_all): CONFIG += build_all
+    qtConfig(debug_and_release): CONFIG += debug_and_release build_all
 }
 
 DEFINES += \
diff --git a/src/core/browser_context_adapter.cpp b/src/core/browser_context_adapter.cpp
index 86808e177..3396f73ef 100644
--- a/src/core/browser_context_adapter.cpp
+++ b/src/core/browser_context_adapter.cpp
@@ -491,19 +491,19 @@ void BrowserContextAdapter::clearHttpCache()
         m_browserContext->url_request_getter_->clearHttpCache();
 }
 
-void BrowserContextAdapter::setSpellCheckLanguage(const QString &language)
+void BrowserContextAdapter::setSpellCheckLanguages(const QStringList &languages)
 {
 #if defined(ENABLE_SPELLCHECK)
-    m_browserContext->setSpellCheckLanguage(language);
+    m_browserContext->setSpellCheckLanguages(languages);
 #endif
 }
 
-QString BrowserContextAdapter::spellCheckLanguage() const
+QStringList BrowserContextAdapter::spellCheckLanguages() const
 {
 #if defined(ENABLE_SPELLCHECK)
-    return m_browserContext->spellCheckLanguage();
+    return m_browserContext->spellCheckLanguages();
 #else
-    return QString();
+    return QStringList();
 #endif
 }
 
diff --git a/src/core/browser_context_adapter.h b/src/core/browser_context_adapter.h
index a6e5a2a3e..39b9db61c 100644
--- a/src/core/browser_context_adapter.h
+++ b/src/core/browser_context_adapter.h
@@ -108,9 +108,8 @@ public:
     QString httpUserAgent() const;
     void setHttpUserAgent(const QString &userAgent);
 
-    QStringList spellCheckLanguages(const QStringList &acceptLanguages);
-    void setSpellCheckLanguage(const QString &language);
-    QString spellCheckLanguage() const;
+    void setSpellCheckLanguages(const QStringList &language);
+    QStringList spellCheckLanguages() const;
     void setSpellCheckEnabled(bool enabled);
     bool isSpellCheckEnabled() const;
 
diff --git a/src/core/browser_context_qt.cpp b/src/core/browser_context_qt.cpp
index 5f544ab86..a6801e1d7 100644
--- a/src/core/browser_context_qt.cpp
+++ b/src/core/browser_context_qt.cpp
@@ -213,18 +213,27 @@ void BrowserContextQt::failedToLoadDictionary(const std::string &language)
                << "Make sure that correct bdic file is in:" << toQt(WebEngineLibraryInfo::getPath(base::DIR_APP_DICTIONARIES).value());
 }
 
-void BrowserContextQt::setSpellCheckLanguage(const QString &language)
+void BrowserContextQt::setSpellCheckLanguages(const QStringList &languages)
 {
-    base::ListValue dictionaries;
-    dictionaries.AppendString(language.toStdString());
-    m_prefService->Set(prefs::kSpellCheckDictionaries, dictionaries);
+    StringListPrefMember dictionaries_pref;
+    dictionaries_pref.Init(prefs::kSpellCheckDictionaries, m_prefService.get());
+    std::vector<std::string> dictionaries;
+    dictionaries.reserve(languages.size());
+    for (const auto &language : languages)
+        dictionaries.push_back(language.toStdString());
+    dictionaries_pref.SetValue(dictionaries);
 }
 
-QString BrowserContextQt::spellCheckLanguage() const
+QStringList BrowserContextQt::spellCheckLanguages() const
 {
-    std::string dictionary;
-    m_prefService->GetList(prefs::kSpellCheckDictionaries)->GetString(0, &dictionary);
-    return QString::fromStdString(dictionary);
+    QStringList spellcheck_dictionaries;
+    for (const auto &value : *m_prefService->GetList(prefs::kSpellCheckDictionaries)) {
+        std::string dictionary;
+        if (value->GetAsString(&dictionary))
+            spellcheck_dictionaries.append(QString::fromStdString(dictionary));
+    }
+
+    return spellcheck_dictionaries;
 }
 
 void BrowserContextQt::setSpellCheckEnabled(bool enabled)
diff --git a/src/core/browser_context_qt.h b/src/core/browser_context_qt.h
index 41a85b1b0..ca65552be 100644
--- a/src/core/browser_context_qt.h
+++ b/src/core/browser_context_qt.h
@@ -101,9 +101,9 @@ public:
     BrowserContextAdapter *adapter() { return m_adapter; }
 
 #if defined(ENABLE_SPELLCHECK)
-    void failedToLoadDictionary(const std::string& language);
-    void setSpellCheckLanguage(const QString &language);
-    QString spellCheckLanguage() const;
+    void failedToLoadDictionary(const std::string& language) override;
+    void setSpellCheckLanguages(const QStringList &languages);
+    QStringList spellCheckLanguages() const;
     void setSpellCheckEnabled(bool enabled);
     bool isSpellCheckEnabled() const;
 #endif
diff --git a/src/core/chrome_qt.gyp b/src/core/chrome_qt.gyp
index 547f240ea..89f1fe188 100644
--- a/src/core/chrome_qt.gyp
+++ b/src/core/chrome_qt.gyp
@@ -113,7 +113,7 @@
             '<(chromium_src_dir)/third_party/WebKit',
           ],
           'dependencies': [
-            '<(chromium_src_dir)/chrome/tools/convert_dict/convert_dict.gyp:convert_dict_lib',
+            '<(chromium_src_dir)/chrome/tools/convert_dict/convert_dict.gyp:convert_dict',
             '<(chromium_src_dir)/third_party/hunspell/hunspell.gyp:hunspell',
             '<(chromium_src_dir)/third_party/icu/icu.gyp:icui18n',
             '<(chromium_src_dir)/third_party/icu/icu.gyp:icuuc',
@@ -132,6 +132,8 @@
               'sources!': [
                 '<(DEPTH)/chrome/renderer/spellchecker/platform_spelling_engine.cc',
                 '<(DEPTH)/chrome/renderer/spellchecker/platform_spelling_engine.h',
+                '<(DEPTH)/chrome/browser/spellchecker/spellcheck_message_filter_platform.h',
+                '<(DEPTH)/chrome/browser/spellchecker/spellcheck_message_filter_platform_mac.cc',
               ],
             }],
           ],
diff --git a/src/core/config/common.pri b/src/core/config/common.pri
index 01c942976..7a9656fca 100644
--- a/src/core/config/common.pri
+++ b/src/core/config/common.pri
@@ -10,3 +10,8 @@ GYP_CONFIG += v8_use_external_startup_data=0
 GYP_CONFIG += enable_web_speech=0
 # We do not use or even include the extensions
 GYP_CONFIG += enable_extensions=0
+
+sanitize_address: GYP_CONFIG += asan=1
+sanitize_thread: GYP_CONFIG += tsan=1
+sanitize_memory: GYP_CONFIG += msan=1
+sanitize_undefined: GYP_CONFIG += ubsan=1
diff --git a/src/core/config/desktop_linux.pri b/src/core/config/desktop_linux.pri
index 46d500207..e28d7eb7c 100644
--- a/src/core/config/desktop_linux.pri
+++ b/src/core/config/desktop_linux.pri
@@ -8,7 +8,11 @@ GYP_CONFIG += \
     enable_pdf=1
 
 clang {
-    GYP_CONFIG += clang=1 host_clang=1 clang_use_chrome_plugins=0 make_clang_dir=/usr
+    GYP_CONFIG += werror=
+    clang_full_path = $$which($${QMAKE_CXX})
+    # Remove the "/bin/clang++" part.
+    clang_prefix = $$section(clang_full_path, /, 0, -3)
+    GYP_CONFIG += clang=1 host_clang=1 clang_use_chrome_plugins=0 make_clang_dir=$${clang_prefix}
     linux-clang-libc++: GYP_CONFIG += use_system_libcxx=1
 } else {
     GYP_CONFIG += clang=0 host_clang=0
diff --git a/src/core/config/linux.pri b/src/core/config/linux.pri
index fc2b124fb..83c852f86 100644
--- a/src/core/config/linux.pri
+++ b/src/core/config/linux.pri
@@ -39,7 +39,7 @@ gcc:!clang: greaterThan(QT_GCC_MAJOR_VERSION, 5): GYP_CONFIG += no_delete_null_p
 qtConfig(system-zlib): use?(system_minizip): GYP_CONFIG += use_system_zlib=1
 qtConfig(system-png): GYP_CONFIG += use_system_libpng=1
 qtConfig(system-jpeg): GYP_CONFIG += use_system_libjpeg=1
-qtConfig(system-harfbuzz): GYP_CONFIG += use_system_harfbuzz=1
+qtConfig(system-harfbuzz): use?(system_harfbuzz): GYP_CONFIG += use_system_harfbuzz=1
 !qtConfig(glib): GYP_CONFIG += use_glib=0
 contains(QT_CONFIG, pulseaudio) {
     GYP_CONFIG += use_pulseaudio=1
diff --git a/src/core/content_browser_client_qt.cpp b/src/core/content_browser_client_qt.cpp
index 64964dc09..787586540 100644
--- a/src/core/content_browser_client_qt.cpp
+++ b/src/core/content_browser_client_qt.cpp
@@ -44,11 +44,15 @@
 #include "base/threading/thread_restrictions.h"
 #if defined(ENABLE_SPELLCHECK)
 #include "chrome/browser/spellchecker/spellcheck_message_filter.h"
+#if defined(USE_BROWSER_SPELLCHECKER)
+#include "chrome/browser/spellchecker/spellcheck_message_filter_platform.h"
+#endif
 #endif
 #include "content/browser/renderer_host/render_view_host_delegate.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/geolocation_delegate.h"
+#include "content/public/browser/client_certificate_delegate.h"
 #include "content/public/browser/media_observer.h"
 #include "content/public/browser/quota_permission_context.h"
 #include "content/public/browser/render_frame_host.h"
@@ -81,6 +85,7 @@
 #if defined(ENABLE_BASIC_PRINTING)
 #include "printing_message_filter_qt.h"
 #endif // defined(ENABLE_BASIC_PRINTING)
+#include "qrc_protocol_handler_qt.h"
 #include "renderer_host/resource_dispatcher_host_delegate_qt.h"
 #include "renderer_host/user_resource_controller_host.h"
 #include "web_contents_delegate_qt.h"
@@ -280,7 +285,8 @@ public:
             m_handle = pni->nativeResourceForContext(QByteArrayLiteral("cglcontextobj"), qtContext);
         else if (platform == QLatin1String("qnx"))
             m_handle = pni->nativeResourceForContext(QByteArrayLiteral("eglcontext"), qtContext);
-        else if (platform == QLatin1String("eglfs") || platform == QLatin1String("wayland"))
+        else if (platform == QLatin1String("eglfs") || platform == QLatin1String("wayland")
+                 || platform == QLatin1String("wayland-egl"))
             m_handle = pni->nativeResourceForContext(QByteArrayLiteral("eglcontext"), qtContext);
         else if (platform == QLatin1String("windows")) {
             if (gl::GetGLImplementation() == gl::kGLImplementationEGLGLES2)
@@ -377,8 +383,12 @@ void ContentBrowserClientQt::RenderProcessWillLaunch(content::RenderProcessHost*
     host->AddFilter(new BrowserMessageFilterQt(id));
 #endif
 #if defined(ENABLE_SPELLCHECK)
+    // SpellCheckMessageFilter is required for both Hunspell and Native configurations.
     host->AddFilter(new SpellCheckMessageFilter(id));
 #endif
+#if defined(Q_OS_MACOS) && defined(USE_BROWSER_SPELLCHECKER)
+  host->AddFilter(new SpellCheckMessageFilterPlatform(id));
+#endif
 #if defined(ENABLE_BASIC_PRINTING)
     host->AddFilter(new PrintingMessageFilterQt(host->GetID()));
 #endif // defined(ENABLE_BASIC_PRINTING)
@@ -472,6 +482,13 @@ void ContentBrowserClientQt::AllowCertificateError(content::WebContents *webCont
         *result = content::CERTIFICATE_REQUEST_RESULT_TYPE_DENY;
 }
 
+void ContentBrowserClientQt::SelectClientCertificate(content::WebContents * /*webContents*/,
+                                                     net::SSLCertRequestInfo * /*certRequestInfo*/,
+                                                     std::unique_ptr<content::ClientCertificateDelegate> delegate)
+{
+    delegate->ContinueWithCertificate(nullptr);
+}
+
 std::string ContentBrowserClientQt::GetApplicationLocale()
 {
     return WebEngineLibraryInfo::getApplicationLocale();
@@ -491,6 +508,11 @@ void ContentBrowserClientQt::AppendExtraCommandLineSwitches(base::CommandLine* c
         command_line->AppendSwitchASCII(switches::kLang, GetApplicationLocale());
 }
 
+void ContentBrowserClientQt::GetAdditionalWebUISchemes(std::vector<std::string>* additional_schemes)
+{
+    additional_schemes->push_back(kQrcSchemeQt);
+}
+
 #if defined(Q_OS_LINUX)
 void ContentBrowserClientQt::GetAdditionalMappedFilesForChildProcess(const base::CommandLine& command_line, int child_process_id, content::FileDescriptorInfo* mappings)
 {
diff --git a/src/core/content_browser_client_qt.h b/src/core/content_browser_client_qt.h
index acbf1a059..a13d14ff2 100644
--- a/src/core/content_browser_client_qt.h
+++ b/src/core/content_browser_client_qt.h
@@ -100,11 +100,15 @@ public:
                                        bool expired_previous_decision,
                                        const base::Callback<void(bool)>& callback,
                                        content::CertificateRequestResultType* result) Q_DECL_OVERRIDE;
+    virtual void SelectClientCertificate(content::WebContents* web_contents,
+                                         net::SSLCertRequestInfo* cert_request_info,
+                                         std::unique_ptr<content::ClientCertificateDelegate> delegate) Q_DECL_OVERRIDE;
     content::DevToolsManagerDelegate *GetDevToolsManagerDelegate() Q_DECL_OVERRIDE;
 
     virtual std::string GetApplicationLocale() Q_DECL_OVERRIDE;
     std::string GetAcceptLangs(content::BrowserContext* context) Q_DECL_OVERRIDE;
     virtual void AppendExtraCommandLineSwitches(base::CommandLine* command_line, int child_process_id) Q_DECL_OVERRIDE;
+    virtual void GetAdditionalWebUISchemes(std::vector<std::string>* additional_schemes) Q_DECL_OVERRIDE;
 
 #if defined(Q_OS_LINUX)
     virtual void GetAdditionalMappedFilesForChildProcess(const base::CommandLine& command_line, int child_process_id, content::FileDescriptorInfo* mappings) Q_DECL_OVERRIDE;
diff --git a/src/core/content_client_qt.cpp b/src/core/content_client_qt.cpp
index 0dac5e48b..5d51f65aa 100644
--- a/src/core/content_client_qt.cpp
+++ b/src/core/content_client_qt.cpp
@@ -166,7 +166,8 @@ void AddPepperFlashFromSystem(std::vector<content::PepperPluginInfo>* plugins)
 #endif
 #if defined(Q_OS_LINUX)
     pluginPaths << "/opt/google/chrome/PepperFlash/libpepflashplayer.so" // Google Chrome
-                << "/usr/lib/pepperflashplugin-nonfree/libpepflashplayer.so" // Ubuntu
+                << "/usr/lib/pepperflashplugin-nonfree/libpepflashplayer.so" // Ubuntu, package pepperflashplugin-nonfree
+                << "/usr/lib/adobe-flashplugin/libpepflashplayer.so" // Ubuntu, package adobe-flashplugin
                 << "/usr/lib/PepperFlash/libpepflashplayer.so" // Arch
                 << "/usr/lib64/chromium/PepperFlash/libpepflashplayer.so"; // OpenSuSE
     pluginPaths << ppapiPluginsPath() + QStringLiteral("/libpepflashplayer.so");
diff --git a/src/core/delegated_frame_node.cpp b/src/core/delegated_frame_node.cpp
index 44e37aeb6..baf064025 100644
--- a/src/core/delegated_frame_node.cpp
+++ b/src/core/delegated_frame_node.cpp
@@ -111,6 +111,10 @@
 #define GL_RGB                            0x1907
 #endif
 
+#ifndef GL_LINE_LOOP
+#define GL_LINE_LOOP                      0x0002
+#endif
+
 namespace QtWebEngineCore {
 #ifndef QT_NO_OPENGL
 class MailboxTexture : public QSGTexture, protected QOpenGLFunctions {
@@ -642,7 +646,7 @@ void DelegatedFrameNode::commit(ChromiumCompositorData *chromiumCompositorData,
                 QSGGeometryNode *geometryNode = new QSGGeometryNode;
 
                 QSGGeometry *geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 4);
-                geometry->setDrawingMode(QSGGeometry::DrawLineLoop);
+                geometry->setDrawingMode(GL_LINE_LOOP);
                 geometry->setLineWidth(dbquad->width);
                 // QSGGeometry::updateRectGeometry would actually set the corners in the following order:
                 // top-left, bottom-left, top-right, bottom-right, leading to a nice criss cross, instead
diff --git a/src/core/doc/src/qtwebenginecore-index.qdoc b/src/core/doc/src/qtwebenginecore-index.qdoc
index 70af397ce..4d540e277 100644
--- a/src/core/doc/src/qtwebenginecore-index.qdoc
+++ b/src/core/doc/src/qtwebenginecore-index.qdoc
@@ -28,7 +28,6 @@
 /*!
     \page qtwebenginecore-index.html
     \title Qt WebEngine Core
-    \ingroup modules
 
     \brief Provides common API shared by Qt WebEngine and Qt WebEngine Widgets.
 
diff --git a/src/core/doc/src/qtwebenginecore-module.qdoc b/src/core/doc/src/qtwebenginecore-module.qdoc
index 6dc2478fc..0ac20a794 100644
--- a/src/core/doc/src/qtwebenginecore-module.qdoc
+++ b/src/core/doc/src/qtwebenginecore-module.qdoc
@@ -32,6 +32,7 @@
     \brief Provides public API shared by both QtWebEngine and QtWebEngineWidgets
     \since 5.6
     \ingroup qtwebengine-modules
+    \ingroup modules
 
     To include the definitions of the module's classes, use the
     following directive:
diff --git a/src/core/gl_context_qt.cpp b/src/core/gl_context_qt.cpp
index b1177a998..a1855b060 100644
--- a/src/core/gl_context_qt.cpp
+++ b/src/core/gl_context_qt.cpp
@@ -122,7 +122,7 @@ void* GLContextHelper::getXConfig()
 
 void* GLContextHelper::getEGLDisplay()
 {
-    return resourceForContext(QByteArrayLiteral("egldisplay"));
+    return resourceForIntegration(QByteArrayLiteral("egldisplay"));
 }
 
 void* GLContextHelper::getXDisplay()
diff --git a/src/core/gl_surface_qt.cpp b/src/core/gl_surface_qt.cpp
index e88a26715..74bb32d1f 100644
--- a/src/core/gl_surface_qt.cpp
+++ b/src/core/gl_surface_qt.cpp
@@ -90,6 +90,9 @@ void* g_display;
 const char* g_extensions = NULL;
 
 bool g_egl_surfaceless_context_supported = false;
+
+bool g_initializedEGL = false;
+
 }  // namespace
 
 
@@ -573,11 +576,17 @@ bool InitializeGLOneOffPlatform()
         return GLSurfaceQtEGL::InitializeOneOff();
 
     if (GetGLImplementation() == kGLImplementationDesktopGL) {
-#if defined(USE_X11)
-        return GLSurfaceQtGLX::InitializeOneOff();
-#elif defined(OS_WIN)
+#if defined(OS_WIN)
         return GLSurfaceQtWGL::InitializeOneOff();
+#elif defined(USE_X11)
+        if (GLSurfaceQtGLX::InitializeOneOff())
+            return true;
 #endif
+        // Fallback to trying EGL with desktop GL.
+        if (GLSurfaceQtEGL::InitializeOneOff()) {
+            g_initializedEGL = true;
+            return true;
+        }
     }
 
     return false;
@@ -586,40 +595,40 @@ bool InitializeGLOneOffPlatform()
 scoped_refptr<GLSurface>
 CreateOffscreenGLSurface(const gfx::Size& size)
 {
+    scoped_refptr<GLSurface> surface;
     switch (GetGLImplementation()) {
     case kGLImplementationDesktopGLCoreProfile:
     case kGLImplementationDesktopGL: {
-#if defined(USE_X11)
-        scoped_refptr<GLSurface> surface = new GLSurfaceQtGLX(size);
-        if (!surface->Initialize())
-            return NULL;
-        return surface;
-#elif defined(OS_WIN)
-        scoped_refptr<GLSurface> surface = new GLSurfaceQtWGL(size);
-        if (!surface->Initialize())
-            return NULL;
-        return surface;
-#else
-        LOG(ERROR) << "Desktop GL is not supported on this platform.";
-        Q_UNREACHABLE();
-        return NULL;
+#if defined(OS_WIN)
+        surface = new GLSurfaceQtWGL(size);
+        if (surface->Initialize())
+            return surface;
+        break;
+#elif defined(USE_X11)
+        if (!g_initializedEGL) {
+            surface = new GLSurfaceQtGLX(size);
+            if (surface->Initialize())
+                return surface;
+        }
+        // no break
 #endif
     }
     case kGLImplementationEGLGLES2: {
-        scoped_refptr<GLSurface> surface;
         if (g_egl_surfaceless_context_supported)
             surface = new GLSurfacelessQtEGL(size);
         else
             surface = new GLSurfaceQtEGL(size);
 
-        if (!surface->Initialize())
-            return NULL;
-        return surface;
+        if (surface->Initialize())
+            return surface;
+        break;
     }
     default:
-        Q_UNREACHABLE();
-        return NULL;
+        break;
     }
+    LOG(ERROR) << "Requested OpenGL platform is not supported.";
+    Q_UNREACHABLE();
+    return NULL;
 }
 
 scoped_refptr<GLSurface>
diff --git a/src/core/gyp_run.pro b/src/core/gyp_run.pro
index 89b751c4a..1850447e7 100644
--- a/src/core/gyp_run.pro
+++ b/src/core/gyp_run.pro
@@ -36,9 +36,7 @@ force_debug_info {
 # Copy this logic from qt_module.prf so that ninja can run according
 # to the same rules as the final module linking in core_module.pro.
 !host_build:if(win32|mac):!macx-xcode {
-    qtConfig(simulator_and_device): CONFIG += simulator_and_device
-    qtConfig(debug_and_release): CONFIG += debug_and_release
-    qtConfig(build_all): CONFIG += build_all
+    qtConfig(debug_and_release): CONFIG += debug_and_release build_all
 }
 
 cross_compile {
@@ -122,12 +120,18 @@ contains(WEBENGINE_CONFIG, use_appstore_compliant_code): GYP_CONFIG += appstore_
 # but the latter are necessary for useful debug binaries.
 contains(WEBENGINE_CONFIG, reduce_binary_size): GYP_CONFIG += release_optimize=s debug_optimize=s release_unwind_tables=0
 
-contains(WEBENGINE_CONFIG, no_spellcheck): {
+!contains(WEBENGINE_CONFIG, use_spellchecker): {
     GYP_CONFIG += enable_spellcheck=0
-    osx: GYP_CONFIG += use_browser_spellchecker=0
+    macos: GYP_CONFIG += use_browser_spellchecker=0
 } else {
     GYP_CONFIG += enable_spellcheck=1
-    osx: GYP_CONFIG += use_browser_spellchecker=1
+    macos {
+        contains(WEBENGINE_CONFIG, use_native_spellchecker) {
+            GYP_CONFIG += use_browser_spellchecker=1
+        } else {
+            GYP_CONFIG += use_browser_spellchecker=0
+        }
+    }
 }
 
 !qtConfig(framework):qtConfig(private_tests) {
diff --git a/src/core/media_capture_devices_dispatcher.cpp b/src/core/media_capture_devices_dispatcher.cpp
index 3e260587c..f06f0150f 100644
--- a/src/core/media_capture_devices_dispatcher.cpp
+++ b/src/core/media_capture_devices_dispatcher.cpp
@@ -173,7 +173,6 @@ void MediaCaptureDevicesDispatcher::handleMediaAccessPermissionResponse(content:
     if (securityOriginsMatch && (microphoneRequested || webcamRequested)) {
         switch (request.request_type) {
         case content::MEDIA_OPEN_DEVICE_PEPPER_ONLY:
-            Q_UNREACHABLE(); // only speculative as this is for Pepper
             getDefaultDevices("", "", microphoneRequested, webcamRequested, &devices);
             break;
         case content::MEDIA_DEVICE_ACCESS:
diff --git a/src/core/pdfium_printing_wrapper_qt.cpp b/src/core/pdfium_printing_wrapper_qt.cpp
index 165ac743f..fceb381af 100644
--- a/src/core/pdfium_printing_wrapper_qt.cpp
+++ b/src/core/pdfium_printing_wrapper_qt.cpp
@@ -139,7 +139,9 @@ PdfiumPrintingWrapperQt::PdfiumPrintingWrapperQt(const void *pdfData, size_t siz
 bool PdfiumPrintingWrapperQt::printOnPrinter(QPrinter &printer)
 {
     if (!m_documentHandle || !m_pageCount) {
+#if QT_VERSION >= QT_VERSION_CHECK(5, 7, 0)
         qWarning("Failure to print on printer %ls: invalid document.\n", qUtf16Printable(printer.printerName()));
+#endif
         return false;
     }
 
@@ -172,7 +174,9 @@ bool PdfiumPrintingWrapperQt::printOnPrinter(QPrinter &printer)
 
     QPainter painter;
     if (!painter.begin(&printer)) {
+#if QT_VERSION >= QT_VERSION_CHECK(5, 7, 0)
         qWarning("Failure to print on printer %ls: Could not open printer for painting.\n", qUtf16Printable(printer.printerName()));
+#endif
         return false;
     }
 
diff --git a/src/core/print_view_manager_qt.cpp b/src/core/print_view_manager_qt.cpp
index 8f52cc24a..0231df8bd 100644
--- a/src/core/print_view_manager_qt.cpp
+++ b/src/core/print_view_manager_qt.cpp
@@ -136,14 +136,16 @@ static base::DictionaryValue *createPrintSettings()
     return printSettings;
 }
 
-static void applyQPageLayoutSettingsToDictionary(const QPageLayout &pageLayout, base::DictionaryValue &printSettings)
+static base::DictionaryValue *createPrintSettingsFromQPageLayout(const QPageLayout &pageLayout)
 {
+    base::DictionaryValue *printSettings = createPrintSettings();
+
     //Set page size attributes, chromium expects these in micrometers
     QSizeF pageSizeInMilimeter = pageLayout.pageSize().size(QPageSize::Millimeter);
     std::unique_ptr<base::DictionaryValue> sizeDict(new base::DictionaryValue);
     sizeDict->SetInteger(printing::kSettingMediaSizeWidthMicrons, pageSizeInMilimeter.width() * kMicronsToMillimeter);
     sizeDict->SetInteger(printing::kSettingMediaSizeHeightMicrons, pageSizeInMilimeter.height() * kMicronsToMillimeter);
-    printSettings.Set(printing::kSettingMediaSize, std::move(sizeDict));
+    printSettings->Set(printing::kSettingMediaSize, std::move(sizeDict));
 
     // Apply page margins
     QMargins pageMarginsInPoints = pageLayout.marginsPoints();
@@ -152,10 +154,13 @@ static void applyQPageLayoutSettingsToDictionary(const QPageLayout &pageLayout,
     marginsDict->SetInteger(printing::kSettingMarginBottom, pageMarginsInPoints.bottom());
     marginsDict->SetInteger(printing::kSettingMarginLeft, pageMarginsInPoints.left());
     marginsDict->SetInteger(printing::kSettingMarginRight, pageMarginsInPoints.right());
-    printSettings.Set(printing::kSettingMarginsCustom, std::move(marginsDict));
-    printSettings.SetInteger(printing::kSettingMarginsType, printing::CUSTOM_MARGINS);
 
-    printSettings.SetBoolean(printing::kSettingLandscape, pageLayout.orientation() == QPageLayout::Landscape);
+    printSettings->Set(printing::kSettingMarginsCustom, std::move(marginsDict));
+    printSettings->SetInteger(printing::kSettingMarginsType, printing::CUSTOM_MARGINS);
+
+    printSettings->SetBoolean(printing::kSettingLandscape, pageLayout.orientation() == QPageLayout::Landscape);
+
+    return printSettings;
 }
 
 } // namespace
@@ -209,12 +214,11 @@ bool PrintViewManagerQt::PrintToPDFInternal(const QPageLayout &pageLayout, bool
 {
     if (!pageLayout.isValid())
         return false;
-    m_printSettings.reset(createPrintSettings());
 
-    m_printSettings->SetInteger(printing::kSettingColor, printInColor ? printing::COLOR : printing::GRAYSCALE);
-    applyQPageLayoutSettingsToDictionary(pageLayout, *m_printSettings);
+    m_printSettings.reset(createPrintSettingsFromQPageLayout(pageLayout));
     m_printSettings->SetBoolean(printing::kSettingShouldPrintBackgrounds
         , web_contents()->GetRenderViewHost()->GetWebkitPreferences().should_print_backgrounds);
+    m_printSettings->SetInteger(printing::kSettingColor, printInColor ? printing::COLOR : printing::GRAYSCALE);
     return Send(new PrintMsg_InitiatePrintPreview(routing_id(), false));
 }
 
diff --git a/src/core/proxy_config_service_qt.cpp b/src/core/proxy_config_service_qt.cpp
index 28a36d37f..a6ffb39ab 100644
--- a/src/core/proxy_config_service_qt.cpp
+++ b/src/core/proxy_config_service_qt.cpp
@@ -109,10 +109,13 @@ net::ProxyConfigService::ConfigAvailability ProxyConfigServiceQt::GetLatestProxy
     }
     m_qtApplicationProxy = qtProxy;
     m_qtProxyConfig = net::ProxyConfig();
-    if (qtProxy.type() == QNetworkProxy::NoProxy) {
+#if QT_VERSION >= QT_VERSION_CHECK(5, 7, 0)
+    if (qtProxy.type() == QNetworkProxy::NoProxy
+            && QNetworkProxyFactory::usesSystemConfiguration()) {
         *config = systemConfig;
         return systemAvailability;
     }
+#endif
 
     net::ProxyConfig::ProxyRules qtRules;
     net::ProxyServer server = fromQNetworkProxy(qtProxy);
diff --git a/src/core/qrc_protocol_handler_qt.cpp b/src/core/qrc_protocol_handler_qt.cpp
index 222961762..eb716f182 100644
--- a/src/core/qrc_protocol_handler_qt.cpp
+++ b/src/core/qrc_protocol_handler_qt.cpp
@@ -46,6 +46,8 @@
 
 namespace QtWebEngineCore {
 
+const char kQrcSchemeQt[] = "qrc";
+
 QrcProtocolHandlerQt::QrcProtocolHandlerQt()
 {
 }
diff --git a/src/core/qrc_protocol_handler_qt.h b/src/core/qrc_protocol_handler_qt.h
index 53d063810..a2e0cc00b 100644
--- a/src/core/qrc_protocol_handler_qt.h
+++ b/src/core/qrc_protocol_handler_qt.h
@@ -53,6 +53,8 @@ class URLRequestJob;
 
 namespace QtWebEngineCore {
 
+extern const char kQrcSchemeQt[];
+
 // Implements a ProtocolHandler for qrc file jobs. If |network_delegate_| is NULL,
 // then all file requests will fail with ERR_ACCESS_DENIED.
 class QrcProtocolHandlerQt : public net::URLRequestJobFactory::ProtocolHandler {
diff --git a/src/core/renderer/content_renderer_client_qt.cpp b/src/core/renderer/content_renderer_client_qt.cpp
index a6e35f4be..69f5bfefe 100644
--- a/src/core/renderer/content_renderer_client_qt.cpp
+++ b/src/core/renderer/content_renderer_client_qt.cpp
@@ -135,6 +135,12 @@ void ContentRendererClientQt::RenderFrameCreated(content::RenderFrame* render_fr
 
 void ContentRendererClientQt::RunScriptsAtDocumentStart(content::RenderFrame* render_frame)
 {
+    // Check whether the render_frame has been created and has not been detached yet.
+    // Otherwise the WebFrame is not available.
+    RenderFrameObserverQt *render_frame_observer = RenderFrameObserverQt::Get(render_frame);
+    if (!render_frame_observer || render_frame_observer->isFrameDetached())
+        return; // The frame is invisible to scripts.
+
     if (WebChannelIPCTransport *transport = WebChannelIPCTransport::Get(render_frame->GetRenderView()))
         transport->RunScriptsAtDocumentStart(render_frame);
     UserResourceController::instance()->RunScriptsAtDocumentStart(render_frame);
@@ -142,6 +148,12 @@ void ContentRendererClientQt::RunScriptsAtDocumentStart(content::RenderFrame* re
 
 void ContentRendererClientQt::RunScriptsAtDocumentEnd(content::RenderFrame* render_frame)
 {
+    // Check whether the render_frame has been created and has not been detached yet.
+    // Otherwise the WebFrame is not available.
+    RenderFrameObserverQt *render_frame_observer = RenderFrameObserverQt::Get(render_frame);
+    if (!render_frame_observer || render_frame_observer->isFrameDetached())
+        return; // The frame is invisible to scripts.
+
     UserResourceController::instance()->RunScriptsAtDocumentEnd(render_frame);
 }
 
diff --git a/src/core/renderer/render_frame_observer_qt.cpp b/src/core/renderer/render_frame_observer_qt.cpp
index 77bc89f67..53e9407db 100644
--- a/src/core/renderer/render_frame_observer_qt.cpp
+++ b/src/core/renderer/render_frame_observer_qt.cpp
@@ -55,6 +55,8 @@ namespace QtWebEngineCore {
 
 RenderFrameObserverQt::RenderFrameObserverQt(content::RenderFrame* render_frame)
     : RenderFrameObserver(render_frame)
+    , RenderFrameObserverTracker<RenderFrameObserverQt>(render_frame)
+    , m_isFrameDetached(false)
 {
 }
 
@@ -72,4 +74,14 @@ void RenderFrameObserverQt::DidCreatePepperPlugin(content::RendererPpapiHost* ho
 }
 #endif
 
+void RenderFrameObserverQt::FrameDetached()
+{
+    m_isFrameDetached = true;
+}
+
+bool RenderFrameObserverQt::isFrameDetached() const
+{
+    return m_isFrameDetached;
+}
+
 } // namespace QtWebEngineCore
diff --git a/src/core/renderer/render_frame_observer_qt.h b/src/core/renderer/render_frame_observer_qt.h
index c59b7babc..b74be5cd1 100644
--- a/src/core/renderer/render_frame_observer_qt.h
+++ b/src/core/renderer/render_frame_observer_qt.h
@@ -42,6 +42,7 @@
 
 #include "base/compiler_specific.h"
 #include "content/public/renderer/render_frame_observer.h"
+#include "content/public/renderer/render_frame_observer_tracker.h"
 
 
 namespace content {
@@ -50,7 +51,10 @@ class RenderFrame;
 
 namespace QtWebEngineCore {
 
-class RenderFrameObserverQt : public content::RenderFrameObserver {
+class RenderFrameObserverQt
+        : public content::RenderFrameObserver
+        , public content::RenderFrameObserverTracker<RenderFrameObserverQt>
+{
 public:
     explicit RenderFrameObserverQt(content::RenderFrame* render_frame);
     ~RenderFrameObserverQt();
@@ -59,9 +63,14 @@ public:
     void DidCreatePepperPlugin(content::RendererPpapiHost* host) override;
 #endif
     void OnDestruct() override { }
+    void FrameDetached() override;
+
+    bool isFrameDetached() const;
 
 private:
     DISALLOW_COPY_AND_ASSIGN(RenderFrameObserverQt);
+
+    bool m_isFrameDetached;
 };
 
 } // namespace QtWebEngineCore
diff --git a/src/core/renderer/web_channel_ipc_transport.cpp b/src/core/renderer/web_channel_ipc_transport.cpp
index 3a44bb182..161d6f493 100644
--- a/src/core/renderer/web_channel_ipc_transport.cpp
+++ b/src/core/renderer/web_channel_ipc_transport.cpp
@@ -164,9 +164,8 @@ void WebChannelIPCTransport::RunScriptsAtDocumentStart(content::RenderFrame *ren
 {
     // JavaScript run before this point doesn't stick, and needs to be redone.
     // ### FIXME: we should try no even installing before
-    blink::WebLocalFrame *frame = render_frame->GetWebFrame();
     if (m_installed && render_frame->IsMainFrame())
-        WebChannelTransport::Install(frame, m_installedWorldId);
+        WebChannelTransport::Install(render_frame->GetWebFrame(), m_installedWorldId);
 }
 
 
@@ -224,9 +223,12 @@ void WebChannelIPCTransport::dispatchWebChannelMessage(const std::vector<char> &
     }
 
     v8::Handle<v8::Object> messageObject(v8::Object::New(isolate));
-    messageObject->ForceSet(v8::String::NewFromUtf8(isolate, "data")
-                       , v8::String::NewFromUtf8(isolate, json.constData(), v8::String::kNormalString, json.size())
-                       , v8::PropertyAttribute(v8::ReadOnly | v8::DontDelete));
+    v8::Maybe<bool> wasSet = messageObject->DefineOwnProperty(
+                context,
+                v8::String::NewFromUtf8(isolate, "data"),
+                v8::String::NewFromUtf8(isolate, json.constData(), v8::String::kNormalString, json.size()),
+                v8::PropertyAttribute(v8::ReadOnly | v8::DontDelete));
+    Q_ASSERT(!wasSet.IsNothing() && wasSet.FromJust());
 
     v8::Handle<v8::Function> callback = v8::Handle<v8::Function>::Cast(onmessageCallbackValue);
     const int argc = 1;
diff --git a/src/core/url_request_context_getter_qt.cpp b/src/core/url_request_context_getter_qt.cpp
index 61f359a87..bf4661102 100644
--- a/src/core/url_request_context_getter_qt.cpp
+++ b/src/core/url_request_context_getter_qt.cpp
@@ -91,8 +91,6 @@
 
 namespace QtWebEngineCore {
 
-static const char kQrcSchemeQt[] = "qrc";
-
 using content::BrowserThread;
 
 URLRequestContextGetterQt::URLRequestContextGetterQt(QSharedPointer<BrowserContextAdapter> browserContext, content::ProtocolHandlerMap *protocolHandlers, content::URLRequestInterceptorScopedVector request_interceptors)
diff --git a/src/core/web_contents_adapter.cpp b/src/core/web_contents_adapter.cpp
index c8d93b3f0..fadbd6d2e 100644
--- a/src/core/web_contents_adapter.cpp
+++ b/src/core/web_contents_adapter.cpp
@@ -351,7 +351,6 @@ WebContentsAdapterPrivate::WebContentsAdapterPrivate()
     , adapterClient(0)
     , nextRequestId(CallbackDirectory::ReservedCallbackIdsEnd)
     , lastFindRequestId(0)
-    , currentDropData(nullptr)
     , currentDropAction(Qt::IgnoreAction)
     , inDragUpdateLoop(false)
     , updateDragCursorMessagePollingTimer(new QTimer)
@@ -1114,18 +1113,12 @@ void WebContentsAdapter::setWebChannel(QWebChannel *channel, uint worldId)
 static QMimeData *mimeDataFromDropData(const content::DropData &dropData)
 {
     QMimeData *mimeData = new QMimeData();
-    if (!dropData.text.is_null()) {
+    if (!dropData.text.is_null())
         mimeData->setText(toQt(dropData.text.string()));
-        return mimeData;
-    }
-    if (!dropData.html.is_null()) {
+    if (!dropData.html.is_null())
         mimeData->setHtml(toQt(dropData.html.string()));
-        return mimeData;
-    }
-    if (dropData.url.is_valid()) {
+    if (dropData.url.is_valid())
         mimeData->setUrls(QList<QUrl>() << toQt(dropData.url));
-        return mimeData;
-    }
     return mimeData;
 }
 
@@ -1140,15 +1133,14 @@ void WebContentsAdapter::startDragging(QObject *dragSource, const content::DropD
 
     // Clear certain fields of the drop data to not run into DCHECKs
     // of DropDataToWebDragData in render_view_impl.cc.
-    content::DropData fixedDropData = dropData;
-    fixedDropData.download_metadata.clear();
-    fixedDropData.file_contents.clear();
-    fixedDropData.file_description_filename.clear();
+    d->currentDropData.reset(new content::DropData(dropData));
+    d->currentDropData->download_metadata.clear();
+    d->currentDropData->file_contents.clear();
+    d->currentDropData->file_description_filename.clear();
 
     d->currentDropAction = Qt::IgnoreAction;
-    d->currentDropData = &fixedDropData;
     QDrag *drag = new QDrag(dragSource);    // will be deleted by Qt's DnD implementation
-    drag->setMimeData(mimeDataFromDropData(fixedDropData));
+    drag->setMimeData(mimeDataFromDropData(*d->currentDropData));
     if (!pixmap.isNull()) {
         drag->setPixmap(pixmap);
         drag->setHotSpot(offset);
@@ -1161,7 +1153,7 @@ void WebContentsAdapter::startDragging(QObject *dragSource, const content::DropD
 
     content::RenderViewHost *rvh = d->webContents->GetRenderViewHost();
     rvh->DragSourceSystemDragEnded();
-    d->currentDropData = nullptr;
+    d->currentDropData.reset();
 }
 
 static blink::WebDragOperationsMask toWeb(const Qt::DropActions action)
@@ -1198,17 +1190,15 @@ void WebContentsAdapter::enterDrag(QDragEnterEvent *e, const QPoint &screenPos)
 {
     Q_D(WebContentsAdapter);
 
-    std::unique_ptr<content::DropData> ownedDropData;
-    const content::DropData *rvhDropData = d->currentDropData;
-    if (!rvhDropData) {
+    if (!d->currentDropData) {
         // The drag originated outside the WebEngineView.
-        ownedDropData.reset(new content::DropData);
-        fillDropDataFromMimeData(ownedDropData.get(), e->mimeData());
-        rvhDropData = ownedDropData.get();
+        d->currentDropData.reset(new content::DropData);
+        fillDropDataFromMimeData(d->currentDropData.get(), e->mimeData());
     }
 
     content::RenderViewHost *rvh = d->webContents->GetRenderViewHost();
-    rvh->DragTargetDragEnter(*rvhDropData, toGfx(e->pos()), toGfx(screenPos),
+    rvh->FilterDropData(d->currentDropData.get());
+    rvh->DragTargetDragEnter(*d->currentDropData, toGfx(e->pos()), toGfx(screenPos),
                              toWeb(e->possibleActions()),
                              flagsFromModifiers(e->keyboardModifiers()));
 }
@@ -1220,6 +1210,16 @@ Qt::DropAction WebContentsAdapter::updateDragPosition(QDragMoveEvent *e, const Q
     rvh->DragTargetDragOver(toGfx(e->pos()), toGfx(screenPos), toWeb(e->possibleActions()),
                             blink::WebInputEvent::LeftButtonDown);
 
+    base::MessageLoop *currentMessageLoop = base::MessageLoop::current();
+    DCHECK(currentMessageLoop);
+    if (!currentMessageLoop->NestableTasksAllowed()) {
+        // We're already inside a MessageLoop::RunTask call, and scheduled tasks will not be
+        // executed. That means, updateDragAction will never be called, and the RunLoop below will
+        // remain blocked forever.
+        qWarning("WebContentsAdapter::updateDragPosition called from MessageLoop::RunTask.");
+        return Qt::IgnoreAction;
+    }
+
     // Wait until we get notified via RenderViewHostDelegateView::UpdateDragCursor. This calls
     // WebContentsAdapter::updateDragAction that will eventually quit the nested loop.
     base::RunLoop loop;
@@ -1254,7 +1254,9 @@ void WebContentsAdapter::endDragging(const QPoint &clientPos, const QPoint &scre
     Q_D(WebContentsAdapter);
     finishDragUpdate();
     content::RenderViewHost *rvh = d->webContents->GetRenderViewHost();
+    rvh->FilterDropData(d->currentDropData.get());
     rvh->DragTargetDrop(*d->currentDropData, toGfx(clientPos), toGfx(screenPos), 0);
+    d->currentDropData.reset();
 }
 
 void WebContentsAdapter::leaveDrag()
@@ -1263,6 +1265,7 @@ void WebContentsAdapter::leaveDrag()
     finishDragUpdate();
     content::RenderViewHost *rvh = d->webContents->GetRenderViewHost();
     rvh->DragTargetDragLeave();
+    d->currentDropData.reset();
 }
 
 void WebContentsAdapter::initUpdateDragCursorMessagePollingTimer()
diff --git a/src/core/web_contents_adapter_p.h b/src/core/web_contents_adapter_p.h
index 77522d299..23a1aaef4 100644
--- a/src/core/web_contents_adapter_p.h
+++ b/src/core/web_contents_adapter_p.h
@@ -92,7 +92,7 @@ public:
     WebContentsAdapterClient *adapterClient;
     quint64 nextRequestId;
     int lastFindRequestId;
-    const content::DropData *currentDropData;
+    std::unique_ptr<content::DropData> currentDropData;
     Qt::DropAction currentDropAction;
     bool inDragUpdateLoop;
     base::Closure dragUpdateLoopQuitClosure;
diff --git a/src/core/web_contents_delegate_qt.cpp b/src/core/web_contents_delegate_qt.cpp
index 9d0965818..36acfe62e 100644
--- a/src/core/web_contents_delegate_qt.cpp
+++ b/src/core/web_contents_delegate_qt.cpp
@@ -74,6 +74,7 @@
 #include "ui/events/latency_info.h"
 
 #include <QDesktopServices>
+#include <QTimer>
 
 namespace QtWebEngineCore {
 
@@ -107,13 +108,19 @@ content::WebContents *WebContentsDelegateQt::OpenURLFromTab(content::WebContents
     Q_ASSERT(target);
 
     content::NavigationController::LoadURLParams load_url_params(params.url);
+    load_url_params.source_site_instance = params.source_site_instance;
     load_url_params.referrer = params.referrer;
     load_url_params.frame_tree_node_id = params.frame_tree_node_id;
+    load_url_params.redirect_chain = params.redirect_chain;
     load_url_params.transition_type = params.transition;
     load_url_params.extra_headers = params.extra_headers;
     load_url_params.should_replace_current_entry = params.should_replace_current_entry;
     load_url_params.is_renderer_initiated = params.is_renderer_initiated;
     load_url_params.override_user_agent = content::NavigationController::UA_OVERRIDE_TRUE;
+    if (params.uses_post) {
+        load_url_params.load_type = content::NavigationController::LOAD_TYPE_HTTP_POST;
+        load_url_params.post_data = params.post_data;
+    }
 
     target->GetController().LoadURLWithParams(load_url_params);
     return target;
@@ -320,7 +327,11 @@ void WebContentsDelegateQt::RunFileChooser(content::RenderFrameHost *frameHost,
 
     m_filePickerController.reset(new FilePickerController(static_cast<FilePickerController::FileChooserMode>(params.mode),
                                                           web_contents(), toQt(params.default_file_name.value()), acceptedMimeTypes));
-    m_viewClient->runFileChooser(m_filePickerController);
+
+    // Defer the call to not block base::MessageLoop::RunTask with modal dialogs.
+    QTimer::singleShot(0, [this] () {
+        m_viewClient->runFileChooser(m_filePickerController);
+    });
 }
 
 bool WebContentsDelegateQt::AddMessageToConsole(content::WebContents *source, int32_t level, const base::string16 &message, int32_t line_no, const base::string16 &source_id)
diff --git a/src/core/web_engine_context.cpp b/src/core/web_engine_context.cpp
index 7fe8fb612..491835e45 100644
--- a/src/core/web_engine_context.cpp
+++ b/src/core/web_engine_context.cpp
@@ -309,8 +309,10 @@ WebEngineContext::WebEngineContext()
 
     if (useEmbeddedSwitches) {
         // Inspired by the Android port's default switches
-        parsedCommandLine->AppendSwitch(switches::kEnableOverlayScrollbar);
-        parsedCommandLine->AppendSwitch(switches::kEnablePinch);
+        if (!parsedCommandLine->HasSwitch(switches::kDisableOverlayScrollbar))
+            parsedCommandLine->AppendSwitch(switches::kEnableOverlayScrollbar);
+        if (!parsedCommandLine->HasSwitch(switches::kDisablePinch))
+            parsedCommandLine->AppendSwitch(switches::kEnablePinch);
         parsedCommandLine->AppendSwitch(switches::kEnableViewport);
         parsedCommandLine->AppendSwitch(switches::kMainFrameResizesAreOrientationChanges);
         parsedCommandLine->AppendSwitch(switches::kDisableAcceleratedVideoDecode);
@@ -325,7 +327,7 @@ WebEngineContext::WebEngineContext()
     const char *glType = 0;
 #ifndef QT_NO_OPENGL
     if (!usingANGLE() && !usingSoftwareDynamicGL() && !usingQtQuick2DRenderer()) {
-        if (qt_gl_global_share_context()) {
+        if (qt_gl_global_share_context() && qt_gl_global_share_context()->isValid()) {
             if (!strcmp(qt_gl_global_share_context()->nativeHandle().typeName(), "QEGLNativeContext")) {
                 if (qt_gl_global_share_context()->isOpenGLES()) {
                     glType = gl::kGLImplementationEGLName;
@@ -359,16 +361,7 @@ WebEngineContext::WebEngineContext()
                     glType = gl::kGLImplementationDesktopName;
             }
         } else {
-            qWarning("WebEngineContext used before QtWebEngine::initialize()");
-            // We have to assume the default OpenGL module type will be used.
-            switch (QOpenGLContext::openGLModuleType()) {
-            case QOpenGLContext::LibGL:
-                glType = gl::kGLImplementationDesktopName;
-                break;
-            case QOpenGLContext::LibGLES:
-                glType = gl::kGLImplementationEGLName;
-                break;
-            }
+            qWarning("WebEngineContext used before QtWebEngine::initialize() or OpenGL context creation failed.");
         }
     }
 #endif
diff --git a/src/core/web_engine_library_info.cpp b/src/core/web_engine_library_info.cpp
index 2be59d1c6..40977812d 100644
--- a/src/core/web_engine_library_info.cpp
+++ b/src/core/web_engine_library_info.cpp
@@ -69,7 +69,7 @@ QString fallbackDir() {
     return directory;
 }
 
-#if defined(OS_MACOSX)
+#if defined(OS_MACOSX) && defined(QT_MAC_FRAMEWORK_BUILD)
 static inline CFBundleRef frameworkBundle()
 {
     return CFBundleGetBundleWithIdentifier(CFSTR("org.qt-project.Qt.QtWebEngineCore"));
@@ -112,6 +112,34 @@ static QString getResourcesPath(CFBundleRef frameworkBundle)
 }
 #endif
 
+#if defined(OS_MACOSX)
+static QString getMainApplicationResourcesPath()
+{
+    QString resourcesPath;
+    CFBundleRef mainBundle = CFBundleGetMainBundle();
+    if (!mainBundle)
+        return resourcesPath;
+
+    // Will point to Resources inside an app bundle, or in case if the application is not packaged
+    // as a bundle, will point to the application directory, where the resources are assumed to be
+    // found.
+    CFURLRef resourcesRelativeUrl = CFBundleCopyResourcesDirectoryURL(mainBundle);
+    if (!resourcesRelativeUrl)
+        return resourcesPath;
+
+    CFURLRef resourcesAbsoluteUrl = CFURLCopyAbsoluteURL(resourcesRelativeUrl);
+    CFStringRef resourcesAbolutePath = CFURLCopyFileSystemPath(resourcesAbsoluteUrl,
+                                                                kCFURLPOSIXPathStyle);
+    resourcesPath = QString::fromCFString(resourcesAbolutePath);
+    CFRelease(resourcesAbolutePath);
+    CFRelease(resourcesAbsoluteUrl);
+    CFRelease(resourcesRelativeUrl);
+
+    return resourcesPath;
+}
+
+#endif
+
 QString subProcessPath()
 {
     static QString processPath;
@@ -181,18 +209,42 @@ QString localesPath()
 #if defined(ENABLE_SPELLCHECK)
 QString dictionariesPath()
 {
+    static QString potentialDictionariesPath;
+    static bool initialized = false;
+    QStringList candidatePaths;
+    if (!initialized) {
+        initialized = true;
+
+        // First try to find dictionaries near the application.
+#ifdef OS_MACOSX
+        QString resourcesDictionariesPath = getMainApplicationResourcesPath()
+                % QDir::separator() % QLatin1String("qtwebengine_dictionaries");
+        candidatePaths << resourcesDictionariesPath;
+#endif
+        QString applicationDictionariesPath = QCoreApplication::applicationDirPath()
+                % QDir::separator() % QLatin1String("qtwebengine_dictionaries");
+        candidatePaths << applicationDictionariesPath;
+
+        // Then try to find dictionaries near the installed library.
 #if defined(OS_MACOSX) && defined(QT_MAC_FRAMEWORK_BUILD)
-    return getResourcesPath(frameworkBundle()) % QLatin1String("/qtwebengine_dictionaries");
-#else
-    // first local path
-    static QString potentialDictionariesPath = QCoreApplication::applicationDirPath() % QDir::separator() % QLatin1String("qtwebengine_dictionaries");
+        QString frameworkDictionariesPath = getResourcesPath(frameworkBundle())
+                % QLatin1String("/qtwebengine_dictionaries");
+        candidatePaths << frameworkDictionariesPath;
+#endif
+
+        QString libraryDictionariesPath = QLibraryInfo::location(QLibraryInfo::DataPath)
+                % QDir::separator() % QLatin1String("qtwebengine_dictionaries");
+        candidatePaths << libraryDictionariesPath;
 
-    // now global one
-    if (!QFileInfo::exists(potentialDictionariesPath))
-        potentialDictionariesPath = QLibraryInfo::location(QLibraryInfo::DataPath) % QDir::separator() % QLatin1String("qtwebengine_dictionaries");
+        Q_FOREACH (const QString &candidate, candidatePaths) {
+            if (QFileInfo::exists(candidate)) {
+                potentialDictionariesPath = candidate;
+                break;
+            }
+        }
+    }
 
     return potentialDictionariesPath;
-#endif
 }
 #endif // ENABLE_SPELLCHECK