Canvas: composite video on canvas correctly.

Source/core/html/canvas/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 1507 matching lines @@
 
     clipRectsToImageRect(FloatRect(FloatPoint(), imageSource->sourceSize()), &srcRect, &dstRect);
 
     imageSource->adjustDrawRects(&srcRect, &dstRect);
 
     if (srcRect.isEmpty())
         return;
 
     FloatRect dirtyRect = clipBounds;
     if (imageSource->isVideoElement()) {
+        // TODO(dshwang): unify video code into below code to composite correctly; crbug.com/407079
         drawVideo(static_cast<HTMLVideoElement*>(imageSource), srcRect, dstRect);
         computeDirtyRect(dstRect, clipBounds, &dirtyRect);
     } else {
         if (rectContainsTransformedRect(dstRect, clipBounds)) {
             c->drawImage(image.get(), dstRect, srcRect, op, blendMode);
         } else if (isFullCanvasCompositeMode(op)) {
             fullCanvasCompositedDrawImage(image.get(), dstRect, srcRect, op);
         } else if (op == CompositeCopy) {
             clearCanvas();
             c->drawImage(image.get(), dstRect, srcRect, op, blendMode);
@@ skipping 964 matching lines @@
 
 unsigned CanvasRenderingContext2D::hitRegionsCount() const
 {
     if (m_hitRegionManager)
         return m_hitRegionManager->getHitRegionsCount();
 
     return 0;
 }
 
 } // namespace blink