Plumb CompositingReason from Blink to compositor.

Source/core/platform/graphics/GraphicsLayer.cpp

 /*
  * 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 1051 matching lines @@
     m_name = String::format("GraphicsLayer(%p) ", this) + name;
     updateNames();
 }
 
 int GraphicsLayer::debugID() const
 {
     // FIXME: change this to assert m_layer always exists, and remove enum.
     return m_layer ? m_layer->layer()->id() : DebugIDNoCompositedLayer;
 }
 
+void GraphicsLayer::setCompositingReasons(WebKit::WebCompositingReasons reasons)
+{
+    m_layer->layer()->setCompositingReasons(reasons);
+}
+
 void GraphicsLayer::setPosition(const FloatPoint& point)
 {
     m_position = point;
     updateLayerPosition();
 }
 
 void GraphicsLayer::setAnchorPoint(const FloatPoint3D& point)
 {
     m_anchorPoint = point;
     updateAnchorPoint();
@@ skipping 360 matching lines @@
 #ifndef NDEBUG
 void showGraphicsLayerTree(const WebCore::GraphicsLayer* layer)
 {
     if (!layer)
         return;
 
     String output = layer->layerTreeAsText(LayerTreeAsTextDebug | LayerTreeAsTextIncludeVisibleRects);
     fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif