Quick: Add experimental.viewport.devicePixelRatio

This specifies a devicePixelRatio to be used by web content instead of
the QScreen::devicePixelRatio(). This is necessary on non-iOS mobile
devices to remain compatible with the mobile web which assumes
devicePixelRatio is computed as the ratio of actual dpi to 160 dpi.
Non-iOS mobile platforms may use different criteria to determine the
QScreen::devicePixelRatio(), depending on the history of the platform,
or simply leave it at 1.0.

For QNX, this setting gets a reasonable default value so developers
don't have to regularly use this experimental API.

These changes were inspired by the Android Chromium port which uses a
GetDpiScale() to accomplish the same in
content/browser/android/content_view_core_impl.cc.

Change-Id: I1bc8878a47dabcdb6986c4fe5c8c4ac230ae2514
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>

8 files changed, 49 insertions, 18 deletions

diff --git a/src/core/render_widget_host_view_qt.cpp b/src/core/render_widget_host_view_qt.cpp
index e2df54afe..20c1dc4fe 100644
--- a/src/core/render_widget_host_view_qt.cpp
+++ b/src/core/render_widget_host_view_qt.cpp
@@ -46,6 +46,7 @@
 #include "delegated_frame_node.h"
 #include "render_widget_host_view_qt_delegate.h"
 #include "type_conversion.h"
+#include "web_contents_adapter_client.h"
 #include "web_event_factory.h"
 
 #include "cc/output/compositor_frame_ack.h"
@@ -225,7 +226,8 @@ gfx::Size RenderWidgetHostViewQt::GetPhysicalBackingSize() const
         return gfx::Size();
 
     const QScreen* screen = m_delegate->window()->screen();
-    return gfx::ToCeiledSize(gfx::ScaleSize(GetViewBounds().size(), screen->devicePixelRatio()));
+    gfx::SizeF size = toGfx(m_delegate->screenRect().size());
+    return gfx::ToCeiledSize(gfx::ScaleSize(size, screen->devicePixelRatio()));
 }
 
 gfx::NativeView RenderWidgetHostViewQt::GetNativeView() const
@@ -290,7 +292,10 @@ bool RenderWidgetHostViewQt::IsShowing()
 gfx::Rect RenderWidgetHostViewQt::GetViewBounds() const
 {
     QRectF p = m_delegate->screenRect();
-    return gfx::Rect(p.x(), p.y(), p.width(), p.height());
+    float s = dpiScale();
+    gfx::Point p1(floor(p.x() / s), floor(p.y() / s));
+    gfx::Point p2(ceil(p.right() /s), ceil(p.bottom() / s));
+    return gfx::BoundingRect(p1, p2);
 }
 
 // Subclasses should override this method to do what is appropriate to set
@@ -592,6 +597,7 @@ void RenderWidgetHostViewQt::GetScreenInfo(WebKit::WebScreenInfo* results)
     if (!window)
         return;
     GetScreenInfoFromNativeWindow(window, results);
+    results->deviceScaleFactor *= dpiScale();
 }
 
 gfx::Rect RenderWidgetHostViewQt::GetBoundsInRootWindow()
@@ -814,6 +820,11 @@ void RenderWidgetHostViewQt::RemoveExpiredMappings(QTouchEvent *ev)
     m_touchIdMapping.swap(newMap);
 }
 
+float RenderWidgetHostViewQt::dpiScale() const
+{
+    return m_adapterClient->dpiScale();
+}
+
 bool RenderWidgetHostViewQt::IsPopup() const
 {
     return popup_type_ != WebKit::WebPopupTypeNone;
@@ -825,7 +836,7 @@ void RenderWidgetHostViewQt::handleMouseEvent(QMouseEvent* event)
     if (eventType == QEvent::MouseButtonDblClick)
         return;
 
-    WebKit::WebMouseEvent webEvent = WebEventFactory::toWebMouseEvent(event);
+    WebKit::WebMouseEvent webEvent = WebEventFactory::toWebMouseEvent(event, dpiScale());
     if (eventType == QMouseEvent::MouseButtonPress) {
         if (event->button() != m_clickHelper.lastPressButton
             || (event->timestamp() - m_clickHelper.lastPressTimestamp > static_cast<ulong>(qGuiApp->styleHints()->mouseDoubleClickInterval()))
@@ -848,7 +859,7 @@ void RenderWidgetHostViewQt::handleKeyEvent(QKeyEvent *ev)
 
 void RenderWidgetHostViewQt::handleWheelEvent(QWheelEvent *ev)
 {
-    m_host->ForwardWheelEvent(WebEventFactory::toWebWheelEvent(ev));
+    m_host->ForwardWheelEvent(WebEventFactory::toWebWheelEvent(ev, dpiScale()));
 }
 
 void RenderWidgetHostViewQt::handleTouchEvent(QTouchEvent *ev)
@@ -866,7 +877,7 @@ void RenderWidgetHostViewQt::handleTouchEvent(QTouchEvent *ev)
 
         ui::TouchEvent uiEvent(
             toUIEventType(touchPoint.state()),
-            toGfxPoint(touchPoint.pos().toPoint()),
+            toGfxPoint((touchPoint.pos() / dpiScale()).toPoint()),
             0, // flags
             GetMappedTouch(touchPoint.id()),
             timestamp,
@@ -892,7 +903,7 @@ void RenderWidgetHostViewQt::handleTouchEvent(QTouchEvent *ev)
 
 void RenderWidgetHostViewQt::handleHoverEvent(QHoverEvent *ev)
 {
-    m_host->ForwardMouseEvent(WebEventFactory::toWebMouseEvent(ev));
+    m_host->ForwardMouseEvent(WebEventFactory::toWebMouseEvent(ev, dpiScale()));
 }
 
 void RenderWidgetHostViewQt::handleFocusEvent(QFocusEvent *ev)
diff --git a/src/core/render_widget_host_view_qt.h b/src/core/render_widget_host_view_qt.h
index c0905ffeb..e7fab3ff5 100644
--- a/src/core/render_widget_host_view_qt.h
+++ b/src/core/render_widget_host_view_qt.h
@@ -205,6 +205,7 @@ private:
     void ProcessGestures(ui::GestureRecognizer::Gestures *gestures);
     int GetMappedTouch(int qtTouchId);
     void RemoveExpiredMappings(QTouchEvent *ev);
+    float dpiScale() const;
 
     bool IsPopup() const;
 
diff --git a/src/core/type_conversion.h b/src/core/type_conversion.h
index 0f0a8ab60..94e30d72b 100644
--- a/src/core/type_conversion.h
+++ b/src/core/type_conversion.h
@@ -93,6 +93,11 @@ inline QSize toQt(const gfx::Size &size)
     return QSize(size.width(), size.height());
 }
 
+inline gfx::SizeF toGfx(const QSizeF& size)
+{
+  return gfx::SizeF(size.width(), size.height());
+}
+
 inline QSizeF toQt(const gfx::SizeF &size)
 {
     return QSizeF(size.width(), size.height());
diff --git a/src/core/web_contents_adapter.cpp b/src/core/web_contents_adapter.cpp
index c09fc362a..f3caa7478 100644
--- a/src/core/web_contents_adapter.cpp
+++ b/src/core/web_contents_adapter.cpp
@@ -49,6 +49,7 @@
 #include "web_engine_context.h"
 
 #include "base/values.h"
+#include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
@@ -344,3 +345,13 @@ void WebContentsAdapter::runJavaScript(const QString &javaScript, const QString
         rvh->ExecuteJavascriptInWebFrameCallbackResult(toString16(xPath), toString16(javaScript), callback);
     }
 }
+
+void WebContentsAdapter::dpiScaleChanged()
+{
+    Q_D(WebContentsAdapter);
+    content::RenderWidgetHostImpl* impl = NULL;
+    if (d->webContents->GetRenderViewHost())
+        impl = content::RenderWidgetHostImpl::From(d->webContents->GetRenderViewHost());
+    if (impl)
+        impl->NotifyScreenInfoChanged();
+}
diff --git a/src/core/web_contents_adapter.h b/src/core/web_contents_adapter.h
index f631b6d69..4bad8aa9b 100644
--- a/src/core/web_contents_adapter.h
+++ b/src/core/web_contents_adapter.h
@@ -89,6 +89,8 @@ public:
     void enableInspector(bool);
     void runJavaScript(const QString &javaScript, const QString &xPath = QString(), JSCallbackBase * = 0);
 
+    void dpiScaleChanged();
+
 private:
     Q_DISABLE_COPY(WebContentsAdapter);
     Q_DECLARE_PRIVATE(WebContentsAdapter);
diff --git a/src/core/web_contents_adapter_client.h b/src/core/web_contents_adapter_client.h
index c7746ffb1..dad77cf57 100644
--- a/src/core/web_contents_adapter_client.h
+++ b/src/core/web_contents_adapter_client.h
@@ -108,6 +108,7 @@ public:
     virtual void loadingStateChanged() = 0;
     virtual void loadProgressChanged(int progress) = 0;
     virtual QRectF viewportRect() const = 0;
+    virtual qreal dpiScale() const = 0;
     virtual void loadFinished(bool success) = 0;
     virtual void focusContainer() = 0;
     virtual void adoptNewWindow(WebContentsAdapter *newWebContents, WindowOpenDisposition disposition, const QRect & initialGeometry) = 0;
diff --git a/src/core/web_event_factory.cpp b/src/core/web_event_factory.cpp
index d750aa3e0..febad0a3a 100644
--- a/src/core/web_event_factory.cpp
+++ b/src/core/web_event_factory.cpp
@@ -527,15 +527,15 @@ static WebInputEvent::Type webEventTypeForEvent(const QEvent* event)
     }
 }
 
-WebMouseEvent WebEventFactory::toWebMouseEvent(QMouseEvent *ev)
+WebMouseEvent WebEventFactory::toWebMouseEvent(QMouseEvent *ev, double dpiScale)
 {
     WebMouseEvent webKitEvent;
     webKitEvent.timeStampSeconds = currentTimeForEvent(ev);
     webKitEvent.button = mouseButtonForEvent(ev);
     webKitEvent.modifiers = modifiersForEvent(ev);
 
-    webKitEvent.x = webKitEvent.windowX = ev->x();
-    webKitEvent.y = webKitEvent.windowY = ev->y();
+    webKitEvent.x = webKitEvent.windowX = ev->x() / dpiScale;
+    webKitEvent.y = webKitEvent.windowY = ev->y() / dpiScale;
     webKitEvent.globalX = ev->globalX();
     webKitEvent.globalY = ev->globalY();
 
@@ -545,20 +545,20 @@ WebMouseEvent WebEventFactory::toWebMouseEvent(QMouseEvent *ev)
     return webKitEvent;
 }
 
-WebMouseEvent WebEventFactory::toWebMouseEvent(QHoverEvent *ev)
+WebMouseEvent WebEventFactory::toWebMouseEvent(QHoverEvent *ev, double dpiScale)
 {
     WebMouseEvent webKitEvent;
     webKitEvent.timeStampSeconds = currentTimeForEvent(ev);
     webKitEvent.modifiers = modifiersForEvent(ev);
 
-    webKitEvent.x = webKitEvent.windowX = ev->pos().x();
-    webKitEvent.y = webKitEvent.windowY = ev->pos().y();
+    webKitEvent.x = webKitEvent.windowX = ev->pos().x() / dpiScale;
+    webKitEvent.y = webKitEvent.windowY = ev->pos().y() / dpiScale;
 
     webKitEvent.type = webEventTypeForEvent(ev);
     return webKitEvent;
 }
 
-WebKit::WebMouseWheelEvent WebEventFactory::toWebWheelEvent(QWheelEvent *ev)
+WebKit::WebMouseWheelEvent WebEventFactory::toWebWheelEvent(QWheelEvent *ev, double dpiScale)
 {
     WebMouseWheelEvent webEvent;
     webEvent.type = webEventTypeForEvent(ev);
@@ -582,8 +582,8 @@ WebKit::WebMouseWheelEvent WebEventFactory::toWebWheelEvent(QWheelEvent *ev)
     webEvent.deltaX = webEvent.wheelTicksX * wheelScrollLines * cDefaultQtScrollStep;
     webEvent.deltaY = webEvent.wheelTicksY * wheelScrollLines * cDefaultQtScrollStep;
 
-    webEvent.x = webEvent.windowX = ev->x();
-    webEvent.y = webEvent.windowY = ev->y();
+    webEvent.x = webEvent.windowX = ev->x() / dpiScale;
+    webEvent.y = webEvent.windowY = ev->y() / dpiScale;
     webEvent.globalX = ev->globalX();
     webEvent.globalY = ev->globalY();
     return webEvent;
diff --git a/src/core/web_event_factory.h b/src/core/web_event_factory.h
index e5ee91510..29a75a285 100644
--- a/src/core/web_event_factory.h
+++ b/src/core/web_event_factory.h
@@ -57,9 +57,9 @@ QT_END_NAMESPACE
 class WebEventFactory {
 
 public:
-    static WebKit::WebMouseEvent toWebMouseEvent(QMouseEvent*);
-    static WebKit::WebMouseEvent toWebMouseEvent(QHoverEvent*);
-    static WebKit::WebMouseWheelEvent toWebWheelEvent(QWheelEvent*);
+    static WebKit::WebMouseEvent toWebMouseEvent(QMouseEvent*, double dpiScale);
+    static WebKit::WebMouseEvent toWebMouseEvent(QHoverEvent*, double dpiScale);
+    static WebKit::WebMouseWheelEvent toWebWheelEvent(QWheelEvent*, double dpiScale);
     static content::NativeWebKeyboardEvent toWebKeyboardEvent(QKeyEvent*);
 };