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

Source/core/html/canvas/CanvasRenderingContext2D.cpp

Index: Source/core/html/canvas/CanvasRenderingContext2D.cpp
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.cpp b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
index b2701331d1dffccff104b5be49378965be011792..33bea5145e0595fa33c481ad665a904b360b9d74 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.cpp
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
@@ -1191,7 +1191,7 @@ static inline FloatRect normalizeRect(const FloatRect& rect)
         max(rect.height(), -rect.height()));
 }
 
-void CanvasRenderingContext2D::drawImageInternal(Image* image, const FloatRect& srcRect, const FloatRect& dstRect, const CompositeOperator& op, const BlendMode& blendMode)
+template<class T> void CanvasRenderingContext2D::drawImageInternal(T* image, const FloatRect& srcRect, const FloatRect& dstRect, const CompositeOperator& op, const BlendMode& blendMode)
 {
     if (!image)
         return;
@@ -1260,12 +1260,8 @@ void CanvasRenderingContext2D::drawImage(ImageBitmap* bitmap,
         return;
 
     ASSERT(bitmap->height() && bitmap->width());
-
     FloatRect normalizedSrcRect = normalizeRect(srcRect);
     FloatRect normalizedDstRect = normalizeRect(dstRect);
-    FloatRect actualDstRect(FloatPoint(bitmap->bitmapOffset()), bitmap->bitmapSize());
-    actualDstRect.scale(normalizedDstRect.width() / bitmap->width(), normalizedDstRect.height() / bitmap->height());
-    actualDstRect.moveBy(normalizedDstRect.location());
 
     FloatRect imageRect = FloatRect(FloatPoint(), bitmap->bitmapSize());
     if (!srcRect.width() || !srcRect.height()) {
@@ -1275,9 +1271,17 @@ void CanvasRenderingContext2D::drawImage(ImageBitmap* bitmap,
     if (!imageRect.contains(normalizedSrcRect))
         return;
 
-    Image* imageForRendering = bitmap->bitmapImage();
-
-    drawImageInternal(imageForRendering, normalizedSrcRect, actualDstRect, state().m_globalComposite, state().m_globalBlend);
+    if (bitmap->canvasImage()) {
+        FloatRect originalCropRect(bitmap->cropRect());
+        normalizedSrcRect.moveBy(originalCropRect.location());
+        FloatRect actualSrcRect = intersection(originalCropRect, normalizedSrcRect);
+        drawImageInternal(bitmap->canvasImage(), actualSrcRect, normalizedDstRect, state().m_globalComposite, state().m_globalBlend);
+    } else {
+        FloatRect actualDstRect(FloatPoint(bitmap->bitmapOffset()), bitmap->bitmapSize());
+        actualDstRect.scale(normalizedDstRect.width() / bitmap->width(), normalizedDstRect.height() / bitmap->height());
+        actualDstRect.moveBy(normalizedDstRect.location());
+        drawImageInternal(bitmap->bitmapImage().get(), normalizedSrcRect, actualDstRect, state().m_globalComposite, state().m_globalBlend);
+    }
 }
 
 void CanvasRenderingContext2D::drawImage(HTMLImageElement* image, float x, float y, ExceptionCode& ec)
@@ -1611,6 +1615,11 @@ static void drawImageToContext(Image* image, GraphicsContext* context, FloatRect
     context->drawImage(image, dest, src, op);
 }
 
+static void drawImageToContext(SkImage* image, GraphicsContext* context, FloatRect& dest, const FloatRect& src, CompositeOperator op)

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

Don't use skia classes outside of core/platform/ unless there is no other way. 
Here we could take an ImageBitmap instead of SkImage.  Extracting the SkImage
should be taken care of in GraphicsContext.

+{
+    context->drawImage(image, dest, src, op);
+}
+
 static void drawImageToContext(ImageBuffer* imageBuffer, GraphicsContext* context, const FloatRect& dest, const FloatRect& src, CompositeOperator op)
 {
     context->drawImageBuffer(imageBuffer, dest, src, op);