Make 2D canvas disable gpu acceleration when getImageData is called

third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h

Index: third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
diff --git a/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h b/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
index 7c8ce5b9507bac3f9f26466f00b47c12515195c8..e027c565b468e7a4b7bdc2d6409800fa7c2ec406 100644
--- a/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
+++ b/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
@@ -193,6 +193,8 @@ private:
     void unregisterTaskObserver();
     void reportSurfaceCreationFailure();
 
+    void disableAcceleration();
+
     // WebThread::TaskOberver implementation
     void willProcessTask() override;
     void didProcessTask() override;
@@ -257,6 +259,7 @@ private:
     bool m_hibernationScheduled = false;
 
     friend class Canvas2DLayerBridgeTest;
+    friend class CanvasRenderingContext2DTest;
 
     uint32_t m_lastImageId;