Plumb CompositingReason from Blink to compositor.

Source/core/platform/graphics/GraphicsLayer.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 214 matching lines @@
 
     GraphicsLayerClient* client() const { return m_client; }
 
     // Layer name. Only used to identify layers in debug output
     const String& name() const { return m_name; }
     void setName(const String&);
 
     // Layer ID from platform-specific layer. Only used to identify layers in the compositor for debugging purposes.
     int debugID() const;
 
+    void setCompositingReasons(CompositingReasons);
+
     GraphicsLayer* parent() const { return m_parent; };
     void setParent(GraphicsLayer*); // Internal use only.
     
     // Returns true if the layer has the given layer as an ancestor (excluding self).
     bool hasAncestor(GraphicsLayer*) const;
     
     const Vector<GraphicsLayer*>& children() const { return m_children; }
     // Returns true if the child list changed.
     bool setChildren(const Vector<GraphicsLayer*>&);
 
@@ skipping 331 matching lines @@
 
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showGraphicsLayerTree(const WebCore::GraphicsLayer* layer);
 #endif
 
 #endif // GraphicsLayer_h