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 e2919800eed802e5f2de25b2d2fca72547a4750c..07ba4d885feaf40f4edf53c6f5ae63815e6a845f 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;
@@ -162,6 +163,9 @@ class WebLayerTreeView {
                                           WebEventListenerProperties){};
   virtual void setHaveScrollEventHandlers(bool){};
 
+  // Returns the FrameSinkId of the current content::RenderWidget
+  virtual cc::FrameSinkId getFrameSinkId() { return cc::FrameSinkId(); }

[dcheng, 2017/01/23 21:53:32]

It's a bit of a layering violation to refer to content here.

Perhaps... "FrameSinkId of the widget associated with this layer tree view."?

[xlai (Olivia), 2017/01/24 20:54:12]

Done.

+
   // Debugging / dangerous ---------------------------------------------
 
   virtual WebEventListenerProperties eventListenerProperties(