[DevTools] Use device metrics emulation implemented in content.

Source/web/WebViewImpl.h

Index: Source/web/WebViewImpl.h
===================================================================
--- Source/web/WebViewImpl.h	(revision 157211)
+++ Source/web/WebViewImpl.h	(working copy)
@@ -325,6 +325,7 @@
 
     void setIgnoreInputEvents(bool newValue);
     WebDevToolsAgentPrivate* devToolsAgentPrivate() { return m_devToolsAgent.get(); }
+    void setDeviceEmulationScales(bool enabled, float deviceScaleFactor, float rootLayerScale);
 
     WebCore::Color baseBackgroundColor() const { return m_baseBackgroundColor; }
 
@@ -626,6 +627,8 @@
     void doPixelReadbackToCanvas(WebCanvas*, const WebCore::IntRect&);
     void reallocateRenderer();
     void updateLayerTreeViewport();
+    void updateRootLayerTransform();
+    void updateLayerTreeDeviceScaleFactor();
 
     // Helper function: Widens the width of |source| by the specified margins
     // while keeping it smaller than page width.
@@ -724,6 +727,10 @@
 
     bool m_ignoreInputEvents;
 
+    bool m_emulatingDeviceScales;

[pfeldman, 2013/09/19 12:46:05]

Lets assume m_emulatingDeviceScales is m_emulatedDeviceScaleFactor != 0.

[dgozman, 2013/09/19 13:59:38]

Done.

+    float m_rootLayerScale;
+    float m_emulatedDeviceScaleFactor;
+
     // Webkit expects keyPress events to be suppressed if the associated keyDown
     // event was handled. Safari implements this behavior by peeking out the
     // associated WM_CHAR event if the keydown was handled. We emulate