Use SkImage as a backing store for copying 2d Contexts to ImageBitmaps.

Source/core/page/ImageBitmap.h

Index: Source/core/page/ImageBitmap.h
diff --git a/Source/core/page/ImageBitmap.h b/Source/core/page/ImageBitmap.h
index 8b8c01c740152758474622c112de18a4dcdc193b..da08ea49ca3a06d4f1b7487a0ea662f7806038c3 100644
--- a/Source/core/page/ImageBitmap.h
+++ b/Source/core/page/ImageBitmap.h
@@ -30,16 +30,18 @@ public:
     static PassRefPtr<ImageBitmap> create(ImageData*, IntRect);
     static PassRefPtr<ImageBitmap> create(ImageBitmap*, IntRect);
 
-    BitmapImage* bitmapImage() const { return m_bitmap.get(); }
+    PassRefPtr<Image> bitmapImage() const { return m_bitmap; }
+    bool derivedFromCanvas() const { return m_derivedFromCanvas; }
 
-    int bitmapWidth() const { return m_bitmap->width(); }
-    int bitmapHeight() const { return m_bitmap->height(); }
-    IntSize bitmapSize() const { return m_bitmap->size(); }
+    int bitmapWidth() const { return m_bitmapSize.width(); }
+    int bitmapHeight() const { return m_bitmapSize.height(); }
+    IntSize bitmapSize() const { return m_bitmapSize; }
     IntPoint bitmapOffset() const { return m_bitmapOffset; }
 
-    int width() const { return m_size.width(); }
-    int height() const { return m_size.height(); }
-    IntSize size() const { return m_size; }
+    int width() const { return m_cropRect.width(); }
+    int height() const { return m_cropRect.height(); }
+    IntSize size() const { return m_cropRect.size(); }
+    IntRect cropRect() const { return m_cropRect; }
 
     ~ImageBitmap() { };
 
@@ -50,11 +52,14 @@ private:
     ImageBitmap(ImageData*, IntRect);
     ImageBitmap(ImageBitmap*, IntRect);
 
-    RefPtr<BitmapImage> m_bitmap;
+    RefPtr<Image> m_bitmap;

[Justin Novosad, 2013/07/22 15:35:41]

With what we've discussed, should this be CachedImage?

     OwnPtr<ImageBuffer> m_buffer;
 
     IntPoint m_bitmapOffset; // offset applied to the image when it is drawn to the context
-    IntSize m_size; // user defined size of the ImageBitmap
+    IntSize m_bitmapSize; // actual size of the BitmapImage
+    IntRect m_cropRect; // user defined size of the ImageBitmap
+
+    bool m_derivedFromCanvas;
 };
 
 } // namespace WebCore