Insert pinch zoom virtual viewport layers to graphics layer tree.

Source/core/rendering/RenderLayerCompositor.h

 /*
  * Copyright (C) 2009 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 120 matching lines @@
     RenderLayer* enclosingNonStackingClippingLayer(const RenderLayer* layer) const;
 
     // Repaint parts of all composited layers that intersect the given absolute rectangle (or the entire layer if the pointer is null).
     void repaintCompositedLayers(const IntRect* = 0);
 
     // Returns true if the given layer needs it own backing store.
     bool requiresOwnBackingStore(const RenderLayer*, const RenderLayer* compositingAncestorLayer) const;
 
     RenderLayer* rootRenderLayer() const;
     GraphicsLayer* rootGraphicsLayer() const;
+    GraphicsLayer* clipLayer() const;

[trchen, 2013/06/13 21:11:54]

nits: We probably don't need this accessor anymore.

[wjmaclean, 2013/06/14 15:54:16]

Done.

     GraphicsLayer* scrollLayer() const;
 
     enum RootLayerAttachment {
         RootLayerUnattached,
         RootLayerAttachedViaChromeClient,
         RootLayerAttachedViaEnclosingFrame
     };
 
     RootLayerAttachment rootLayerAttachment() const { return m_rootLayerAttachment; }
     void updateRootLayerAttachment();
@@ skipping 213 matching lines @@
     int m_secondaryCompositedLayerCount; // count of layers that have to be composited because of stacking or overlap.
     double m_obligatoryBackingStoreBytes;
     double m_secondaryBackingStoreBytes;
 #endif
 };
 
 
 } // namespace WebCore
 
 #endif // RenderLayerCompositor_h