Sky should use an SkPicture when drawing

sky/compositor/display_delegate.h

-// Copyright 2014 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 SKY_COMPOSITOR_DISPLAY_DELEGATE_H_
-#define SKY_COMPOSITOR_DISPLAY_DELEGATE_H_
-
-#include <vector>
-
-#include "mojo/skia/ganesh_surface.h"
-
-class SkCanvas;
-
-namespace gfx {
-class Rect;
-}
-
-namespace sky {
-
-class DisplayDelegate;
-class LayerClient;
-
-typedef DisplayDelegate* (*CreateDisplayDelegate)(LayerClient*);
-
-class DisplayDelegate {
- public:
-  DisplayDelegate() {}
-  virtual ~DisplayDelegate() {}
-
-  static DisplayDelegate* create(LayerClient*);
-  static void setDisplayDelegateCreateFunction(CreateDisplayDelegate);
-
-  virtual void GetPixelsForTesting(std::vector<unsigned char>* pixels) = 0;
-  virtual void Paint(mojo::GaneshSurface& surface, const gfx::Rect& size) = 0;
-
-  DISALLOW_COPY_AND_ASSIGN(DisplayDelegate);
-};
-
-
-
-}  // namespace sky
-
-#endif  // SKY_COMPOSITOR_DISPLAY_DELEGATE_H_