Refactoring source image usage in CanvasRenderingContext2D

Source/core/frame/ImageBitmap.h

Index: Source/core/frame/ImageBitmap.h
diff --git a/Source/core/frame/ImageBitmap.h b/Source/core/frame/ImageBitmap.h
index 7f62bdaee9948f3105ad84c6f1f62e3ebe3ed015..6b5abfcec7d8899618dd62f016ad7a213ddeabda 100644
--- a/Source/core/frame/ImageBitmap.h
+++ b/Source/core/frame/ImageBitmap.h
@@ -7,6 +7,7 @@
 
 #include "bindings/v8/ScriptWrappable.h"
 #include "core/html/HTMLImageElement.h"
+#include "core/html/canvas/CanvasImageSource.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/graphics/Image.h"
 #include "wtf/PassRefPtr.h"
@@ -18,7 +19,7 @@ class HTMLCanvasElement;
 class HTMLVideoElement;
 class ImageData;
 
-class ImageBitmap FINAL : public RefCounted<ImageBitmap>, public ScriptWrappable, public ImageLoaderClient {
+class ImageBitmap FINAL : public RefCounted<ImageBitmap>, public ScriptWrappable, public ImageLoaderClient, public CanvasImageSource {
 
 public:
     static PassRefPtr<ImageBitmap> create(HTMLImageElement*, const IntRect&);
@@ -32,7 +33,7 @@ public:
     PassRefPtr<HTMLImageElement> imageElement() const { return m_imageElement; }
 
     IntRect bitmapRect() const { return m_bitmapRect; }
-    IntPoint bitmapOffset() const { return m_bitmapOffset; }
+    virtual IntPoint bitmapOffset() const { return m_bitmapOffset; }
 
     int width() const { return m_cropRect.width(); }
     int height() const { return m_cropRect.height(); }
@@ -40,6 +41,12 @@ public:
 
     virtual ~ImageBitmap();
 
+    // CanvasImageSource implementation
+    virtual PassRefPtr<Image> getSourceImageForCanvas(HTMLCanvasElement*, ExceptionState&, CanvasImageSourceUsage, bool* isVolatile) const OVERRIDE;
+    virtual bool wouldTaintOrigin(CanvasRenderingContext*) const OVERRIDE { return false; };
+    virtual void adjustDrawRects(FloatRect* srcRect, FloatRect* dstRect) const OVERRIDE;
+    virtual FloatSize sourceSize() const OVERRIDE;
+
 private:
     ImageBitmap(HTMLImageElement*, const IntRect&);
     ImageBitmap(HTMLVideoElement*, const IntRect&);