Fix performance regression in WebGL to 2D canvas draws.

third_party/WebKit/Source/modules/canvas2d/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 566 matching lines @@
 bool CanvasRenderingContext2D::hasImageBuffer() const
 {
     return canvas()->hasImageBuffer();
 }
 
 ImageBuffer* CanvasRenderingContext2D::imageBuffer() const
 {
     return canvas()->buffer();
 }
 
-PassRefPtr<Image> blink::CanvasRenderingContext2D::getImage(SnapshotReason reason) const
+PassRefPtr<Image> blink::CanvasRenderingContext2D::getImage(AccelerationHint hint, SnapshotReason reason) const
 {
     if (!hasImageBuffer())
         return nullptr;
-    return canvas()->buffer()->newImageSnapshot(PreferAcceleration, reason);
+    return canvas()->buffer()->newImageSnapshot(hint, reason);
 }
 
 bool CanvasRenderingContext2D::parseColorOrCurrentColor(Color& color, const String& colorString) const
 {
     return ::blink::parseColorOrCurrentColor(color, colorString, canvas());
 }
 
 HitTestCanvasResult* CanvasRenderingContext2D::getControlAndIdIfHitRegionExists(const LayoutPoint& location)
 {
     if (hitRegionsCount() <= 0)
@@ skipping 495 matching lines @@
     return true;
 }
 
 void CanvasRenderingContext2D::resetUsageTracking()
 {
     UsageCounters newCounters;
     m_usageCounters = newCounters;
 }
 
 } // namespace blink