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

third_party/WebKit/Source/core/page/ChromeClient.h

Index: third_party/WebKit/Source/core/page/ChromeClient.h
diff --git a/third_party/WebKit/Source/core/page/ChromeClient.h b/third_party/WebKit/Source/core/page/ChromeClient.h
index f4492e9b6ab9c7c57b69bde5e8d3e5d946849cb1..66b4ea068a595c666b9eeeb98090f4f84fb59eb6 100644
--- a/third_party/WebKit/Source/core/page/ChromeClient.h
+++ b/third_party/WebKit/Source/core/page/ChromeClient.h
@@ -72,6 +72,7 @@ class WebDragData;
 class WebFrameScheduler;
 class WebImage;
 class WebLayer;
+class WebLayerTreeView;
 
 struct CompositedSelection;
 struct DateTimeChooserParameters;
@@ -343,6 +344,8 @@ class CORE_EXPORT ChromeClient : public HostWindow {
 
   virtual void installSupplements(LocalFrame&) {}
 
+  virtual WebLayerTreeView* getWebLayerTreeView(LocalFrame*) { return nullptr; }
+
   DECLARE_TRACE();
 
  protected: