cc: Add layer-based pixel tests.

cc/layer_tree_host_impl.h

 // Copyright 2011 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_TREE_HOST_IMPL_H_
 #define CC_LAYER_TREE_HOST_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
@@ skipping 169 matching lines @@
 
   void FinishAllRendering();
   int SourceAnimationFrameNumber() const;
 
   virtual bool InitializeRenderer(scoped_ptr<OutputSurface> output_surface);
   bool IsContextLost();
   TileManager* tile_manager() { return tile_manager_.get(); }
   Renderer* renderer() { return renderer_.get(); }
   const RendererCapabilities& GetRendererCapabilities() const;
 
-  bool SwapBuffers();
+  virtual bool SwapBuffers();
 
   void Readback(void* pixels, gfx::Rect rect_in_device_viewport);
 
   LayerTreeImpl* active_tree() { return active_tree_.get(); }
   const LayerTreeImpl* active_tree() const { return active_tree_.get(); }
   LayerTreeImpl* pending_tree() { return pending_tree_.get(); }
   const LayerTreeImpl* pending_tree() const { return pending_tree_.get(); }
   const LayerTreeImpl* recycle_tree() const { return recycle_tree_.get(); }
   void CreatePendingTree();
   void CheckForCompletedTileUploads();
@@ skipping 236 matching lines @@
   base::TimeTicks current_frame_time_;
 
   scoped_ptr<AnimationRegistrar> animation_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_IMPL_H_