Free temporary GPU and memory resources held by inactive or hidden 2D canvases

Source/platform/graphics/Canvas2DImageBufferSurface.h

Index: Source/platform/graphics/Canvas2DImageBufferSurface.h
diff --git a/Source/platform/graphics/Canvas2DImageBufferSurface.h b/Source/platform/graphics/Canvas2DImageBufferSurface.h
index eed61d04c117aec91bfc3fd110dae2f7cf4bcebf..215230ef4d623de4ae7b0c70c661887d450dc8d5 100644
--- a/Source/platform/graphics/Canvas2DImageBufferSurface.h
+++ b/Source/platform/graphics/Canvas2DImageBufferSurface.h
@@ -59,6 +59,7 @@ public:
     virtual blink::WebLayer* layer() const OVERRIDE { return m_layerBridge->layer(); }
     virtual Platform3DObject getBackingTexture() const OVERRIDE { return m_layerBridge->getBackingTexture(); }
     virtual bool isAccelerated() const OVERRIDE { return m_layerBridge->isAccelerated(); }
+    virtual void setIsHidden(bool hidden) OVERRIDE { m_layerBridge->setIsHidden(hidden); }
 
 private:
     RefPtr<Canvas2DLayerBridge> m_layerBridge;