Remove the forceCompositingMode setting.

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 83 matching lines @@
     virtual void willStartLiveResize() OVERRIDE;
     virtual void resize(const WebSize&) OVERRIDE;
     virtual void resizePinchViewport(const WebSize&) OVERRIDE;
     virtual void willEndLiveResize() OVERRIDE;
     virtual void willEnterFullScreen() OVERRIDE;
     virtual void didEnterFullScreen() OVERRIDE;
     virtual void willExitFullScreen() OVERRIDE;
     virtual void didExitFullScreen() OVERRIDE;
     virtual void animate(double) OVERRIDE;
     virtual void layout() OVERRIDE;
-    virtual void enterForceCompositingMode(bool enable) OVERRIDE;
     virtual void paint(WebCanvas*, const WebRect&) OVERRIDE;
 #if OS(ANDROID)
     virtual void paintCompositedDeprecated(WebCanvas*, const WebRect&) OVERRIDE;
 #endif
     virtual void compositeAndReadbackAsync(WebCompositeAndReadbackAsyncCallback*) OVERRIDE;
     virtual bool isTrackingRepaints() const OVERRIDE;
     virtual void themeChanged() OVERRIDE;
     virtual bool handleInputEvent(const WebInputEvent&) OVERRIDE;
     virtual void setCursorVisibilityState(bool isVisible) OVERRIDE;
     virtual bool hasTouchEventHandlersAt(const WebPoint&) OVERRIDE;
@@ skipping 602 matching lines @@
     bool m_userGestureObserved;
 };
 
 // We have no ways to check if the specified WebView is an instance of
 // WebViewImpl because WebViewImpl is the only implementation of WebView.
 DEFINE_TYPE_CASTS(WebViewImpl, WebView, webView, true, true);
 
 } // namespace blink
 
 #endif