Refactoring ImageBuffer to decouple it from Canvas2DLayerBridge

Source/core/html/HTMLCanvasElement.h

 /*
  * Copyright (C) 2004, 2006, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * 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 27 matching lines @@
 namespace WebCore {
 
 class CanvasContextAttributes;
 class CanvasRenderingContext;
 class GraphicsContext;
 class GraphicsContextStateSaver;
 class HTMLCanvasElement;
 class Image;
 class ImageData;
 class ImageBuffer;
+class ImageBufferSurface;
 class IntSize;
 
 class CanvasObserver {
 public:
     virtual ~CanvasObserver() { }
 
     virtual void canvasChanged(HTMLCanvasElement*, const FloatRect& changedRect) = 0;
     virtual void canvasResized(HTMLCanvasElement*) = 0;
     virtual void canvasDestroyed(HTMLCanvasElement*) = 0;
 };
@@ skipping 70 matching lines @@
 
 private:
     explicit HTMLCanvasElement(Document&);
 
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     virtual RenderObject* createRenderer(RenderStyle*);
     virtual bool areAuthorShadowsAllowed() const OVERRIDE { return false; }
 
     void reset();
 
+    PassOwnPtr<ImageBufferSurface> createImageBufferSurface(const IntSize& deviceSize, int* msaaSampleCount);
     void createImageBuffer();
     void clearImageBuffer();
 
     void setSurfaceSize(const IntSize&);
     IntSize convertLogicalToDevice(const IntSize&) const;
 
     bool paintsIntoCanvasBuffer() const;
 
     void setExternallyAllocatedMemory(intptr_t);
 
@@ skipping 23 matching lines @@
 
     mutable RefPtr<Image> m_presentedImage;
     mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).
 };
 
 DEFINE_NODE_TYPE_CASTS(HTMLCanvasElement, hasTagName(HTMLNames::canvasTag));
 
 } //namespace
 
 #endif