cc: Avoid expensive RenderingStats collection.

cc/layer.h

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYER_H_
 #define CC_LAYER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 191 matching lines @@
     void setReplicaLayer(Layer*);
     Layer* replicaLayer() { return m_replicaLayer.get(); }
     const Layer* replicaLayer() const { return m_replicaLayer.get(); }
 
     bool hasMask() const { return !!m_maskLayer; }
     bool hasReplica() const { return !!m_replicaLayer; }
     bool replicaHasMask() const { return m_replicaLayer && (m_maskLayer || m_replicaLayer->m_maskLayer); }
 
     // These methods typically need to be overwritten by derived classes.
     virtual bool drawsContent() const;
-    virtual void update(ResourceUpdateQueue&, const OcclusionTracker*, RenderingStats&) { }
+    virtual void update(ResourceUpdateQueue&, const OcclusionTracker*, RenderingStats*) { }
     virtual bool needMoreUpdates();
     virtual void setIsMask(bool) { }
 
     void setDebugName(const std::string&);
 
     virtual void pushPropertiesTo(LayerImpl*);
 
     void clearRenderSurface() { m_drawProperties.render_surface.reset(); }
     void createRenderSurface();
 
@@ skipping 181 matching lines @@
     WebKit::WebLayerScrollClient* m_layerScrollClient;
 
     DrawProperties<Layer, RenderSurface> m_drawProperties;
 };
 
 void sortLayers(std::vector<scoped_refptr<Layer> >::iterator, std::vector<scoped_refptr<Layer> >::iterator, void*);
 
 }  // namespace cc
 
 #endif  // CC_LAYER_H_