[DevTools] Use device metrics emulation implemented in content.

Source/web/WebViewImpl.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 612 matching lines @@
                                                DragAction,
                                                int keyModifiers);
 
     void configureAutoResizeMode();
 
     void setIsAcceleratedCompositingActive(bool);
     void doComposite();
     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.
     WebRect widenRectWithinPageBounds(const WebRect& source, int targetMargin, int minimumMargin);
 
     void pointerLockMouseEvent(const WebInputEvent&);
 
     // PageWidgetEventHandler functions
     virtual void handleMouseLeave(WebCore::Frame&, const WebMouseEvent&) OVERRIDE;
     virtual void handleMouseDown(WebCore::Frame&, const WebMouseEvent&) OVERRIDE;
@@ skipping 79 matching lines @@
     WebCore::IntPoint m_fakePageScaleAnimationTargetPosition;
     float m_fakePageScaleAnimationPageScaleFactor;
     bool m_fakePageScaleAnimationUseAnchor;
 
     bool m_contextMenuAllowed;
 
     bool m_doingDragAndDrop;
 
     bool m_ignoreInputEvents;
 
+    float m_compositorDeviceScaleFactorOverride;
+    float m_rootLayerScale;
+
     // 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
     // this behavior by setting this flag if the keyDown was handled.
     bool m_suppressNextKeypressEvent;
 
     // Represents whether or not this object should process incoming IME events.
     bool m_imeAcceptEvents;
 
     // The available drag operations (copy, move link...) allowed by the source.
@@ skipping 91 matching lines @@
 inline WebViewImpl* toWebViewImpl(WebView* webView)
 {
     // We have no ways to check if the specified WebView is an instance of
     // WebViewImpl because WebViewImpl is the only implementation of WebView.
     return static_cast<WebViewImpl*>(webView);
 }
 
 } // namespace WebKit
 
 #endif