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

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple, Inc. All rights
  * reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 54 matching lines @@
 class IntRect;
 class KeyboardEvent;
 class LocalFrame;
 class Node;
 class Page;
 class PopupOpeningObserver;
 class WebDragData;
 class WebFrameScheduler;
 class WebImage;
 class WebLayer;
+class WebLayerTreeView;
 
 struct CompositedSelection;
 struct DateTimeChooserParameters;
 struct FrameLoadRequest;
 struct ViewportDescription;
 struct WebPoint;
 struct WebScreenInfo;
 struct WindowFeatures;
 
 class CORE_EXPORT ChromeClient : public HostWindow {
@@ skipping 250 matching lines @@
 
   virtual std::unique_ptr<WebFrameScheduler> createFrameScheduler(
       BlameContext*) = 0;
 
   // Returns the time of the beginning of the last beginFrame, in seconds, if
   // any, and 0.0 otherwise.
   virtual double lastFrameTimeMonotonic() const { return 0.0; }
 
   virtual void installSupplements(LocalFrame&) {}
 
+  virtual WebLayerTreeView* getWebLayerTreeView() { return nullptr; }
+
   DECLARE_TRACE();
 
  protected:
   ~ChromeClient() override {}
 
   virtual void showMouseOverURL(const HitTestResult&) = 0;
   virtual void setWindowRect(const IntRect&, LocalFrame&) = 0;
   virtual bool openBeforeUnloadConfirmPanelDelegate(LocalFrame*,
                                                     bool isReload) = 0;
   virtual bool openJavaScriptAlertDelegate(LocalFrame*, const String&) = 0;
@@ skipping 13 matching lines @@
   WeakMember<Node> m_lastMouseOverNode;
   LayoutPoint m_lastToolTipPoint;
   String m_lastToolTipText;
 
   FRIEND_TEST_ALL_PREFIXES(ChromeClientTest, SetToolTipFlood);
 };
 
 }  // namespace blink
 
 #endif  // ChromeClient_h