Make OffscreenCanvas animation in sync with its placeholder canvas's parent frame rate

third_party/WebKit/public/platform/WebLayerTreeView.h

Index: third_party/WebKit/public/platform/WebLayerTreeView.h
diff --git a/third_party/WebKit/public/platform/WebLayerTreeView.h b/third_party/WebKit/public/platform/WebLayerTreeView.h
index 6b7889e7eaf4b147d5109ebf0a6727b59c0aad5c..95e02689d9e4807194830c256acaf43c93e4f9b3 100644
--- a/third_party/WebKit/public/platform/WebLayerTreeView.h
+++ b/third_party/WebKit/public/platform/WebLayerTreeView.h
@@ -33,6 +33,7 @@
 #include "WebEventListenerProperties.h"
 #include "WebFloatPoint.h"
 #include "WebSize.h"
+#include "cc/surfaces/frame_sink_id.h"
 
 namespace cc {
 class AnimationHost;
@@ -163,6 +164,9 @@ class WebLayerTreeView {
   virtual void updateTouchRectsForSubframeIfNecessary() {}
   virtual void setHaveScrollEventHandlers(bool) {}
 
+  // Returns the FrameSinkId of the widget associated with this layer tree view.
+  virtual cc::FrameSinkId getFrameSinkId() { return cc::FrameSinkId(); }
+
   // Debugging / dangerous ---------------------------------------------
 
   virtual WebEventListenerProperties eventListenerProperties(