Implement will-change-based GPU rasterization hint

Source/core/rendering/compositing/CompositedLayerMapping.h

 /*
  * Copyright (C) 2009, 2010, 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 230 matching lines @@
     FloatPoint3D computeTransformOrigin(const IntRect& borderBox) const;
     // Result is perspective origin in pixels.
     FloatPoint computePerspectiveOrigin(const IntRect& borderBox) const;
 
     void updateSquashingLayerGeometry(const IntPoint& delta);
 
     void updateOpacity(const RenderStyle*);
     void updateTransform(const RenderStyle*);
     void updateLayerBlendMode(const RenderStyle*);
     void updateIsRootForIsolatedGroup();
+    void updateHasGpuRasterizationHint(const RenderStyle*);
     // Return the opacity value that this layer should use for compositing.
     float compositingOpacity(float rendererOpacity) const;
 
     bool isMainFrameRenderViewLayer() const;
 
     bool paintsChildren() const;
 
     // Returns true if this layer has content that needs to be rendered by painting into the backing store.
     bool containsPaintedContent() const;
     // Returns true if the RenderLayer just contains an image that we can composite directly.
@@ skipping 98 matching lines @@
     bool m_requiresOwnBackingStoreForAncestorReasons : 1;
     bool m_canCompositeFilters : 1;
     bool m_backgroundLayerPaintsFixedRootBackground : 1;
     bool m_needToUpdateGeometry : 1;
     bool m_needToUpdateGeometryOfAllDecendants : 1;
 };
 
 } // namespace WebCore
 
 #endif // CompositedLayerMapping_h