cc: Implement DelegatingRender::drawFrame() method.

cc/compositor_frame.h

 // Copyright 2012 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_COMPOSITOR_FRAME_H_
 #define CC_COMPOSITOR_FRAME_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/cc_export.h"
 #include "cc/compositor_frame_metadata.h"
 #include "cc/delegated_frame_data.h"
 #include "cc/gl_frame_data.h"
 
 namespace cc {
 
 class CC_EXPORT CompositorFrame {
  public:
   CompositorFrame();
   ~CompositorFrame();
 
   CompositorFrameMetadata metadata;
   scoped_ptr<DelegatedFrameData> delegated_frame_data;
   scoped_ptr<GLFrameData> gl_frame_data;
+
+  void AssignTo(CompositorFrame* target);
 };
 
 }  // namespace cc
 
 #endif  // CC_COMPOSITOR_FRAME_H_