Resolving drawImage issue with canvases that contain bitmap images

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 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 1083 matching lines @@
 
     if (!m_context) {
         *status = NormalSourceImageStatus;
         return createTransparentImage(size());
     }
 
     if (m_context->is3d()) {
         m_context->paintRenderingResultsToCanvas(BackBuffer);
     }
 
-    RefPtr<SkImage> image = buffer()->newSkImageSnapshot(hint, reason);
-    if (image) {
+    RefPtr<SkImage> skImage;
+    RefPtr<blink::Image> image = renderingContext()->getImage();
+    if (image)
+        skImage = image->imageForCurrentFrame();
+    else
+        skImage = buffer()->newSkImageSnapshot(hint, reason);

[Justin Novosad, 2016/08/22 20:03:02]

Just realized this code may inadvertently allocate a permanent ImageBuffer,
which should be avoided if possible.  Try this:
skImage = hasImageBuffer() ? buffer()->newSkImageSnapshot(hint, reason) :
createTransparentImage(size());

[zakerinasab, 2016/08/22 20:19:09]

createTransparentImage(size()) returns PassRefPtr<Image>, so I added the call to
imageForCurrentFrame(). Regarding hasImageBuffer(), what is the expected
behavior in our case that we don't have an ImageBuffer to use and we get the
info from m_context? It still returns true.

+
+    if (skImage) {
         *status = NormalSourceImageStatus;
-        return StaticBitmapImage::create(image.release());
+        return StaticBitmapImage::create(skImage.release());
     }
 
     *status = InvalidSourceImageStatus;
     return nullptr;
 }
 
 bool HTMLCanvasElement::wouldTaintOrigin(SecurityOrigin*) const
 {
     return !originClean();
 }
@@ skipping 98 matching lines @@
 
 bool HTMLCanvasElement::createSurfaceLayer()
 {
     DCHECK(!m_surfaceLayerBridge);
     std::unique_ptr<CanvasSurfaceLayerBridgeClient> bridgeClient = wrapUnique(new CanvasSurfaceLayerBridgeClientImpl());
     m_surfaceLayerBridge = wrapUnique(new CanvasSurfaceLayerBridge(std::move(bridgeClient)));
     return m_surfaceLayerBridge->createSurfaceLayer(this->width(), this->height());
 }
 
 } // namespace blink