Resolving drawImage issue with canvases that contain bitmap images

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

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
index f2bfec4694d5ea0db8288d6798317bef582b67cc..526dcca8c5648267c14b5e3b53a657c4616f2ca1 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
@@ -1101,10 +1101,16 @@ PassRefPtr<Image> HTMLCanvasElement::getSourceImageForCanvas(SourceImageStatus*
         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;