Make CanvasRenderingContext2D use SkCanvas directly

Source/platform/graphics/ImageBuffer.h

 /*
  * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 84 matching lines @@
     void didDraw() const { m_surface->didDraw(); }
 
     void setFilterLevel(SkPaint::FilterLevel filterLevel) { m_surface->setFilterLevel(filterLevel); }
     void setIsHidden(bool hidden) { m_surface->setIsHidden(hidden); }
 
     // Called by subclasses of ImageBufferSurface to install a new canvas object
     void resetCanvas(SkCanvas*);
 
     void willDrawVideo() { m_surface->willDrawVideo(); }
 
-    GraphicsContext* context() const;
+    GraphicsContext* context() const; // Deprecated: use canvas()
+    SkCanvas* canvas() const;
 
     // Called at the end of a task that rendered a whole frame
     void finalizeFrame(const FloatRect &dirtyRect);
     void didFinalizeFrame();
 
     bool isDirty();
 
     const SkBitmap& bitmap() const;
 
     void willAccessPixels() { m_surface->willAccessPixels(); }
@@ skipping 50 matching lines @@
     unsigned char* pixels() const { return m_data; }
     int height() const { return m_size.height(); }
     int width() const { return m_size.width(); }
     unsigned char* m_data;
     IntSize m_size;
 };
 
 } // namespace blink
 
 #endif // ImageBuffer_h