Make RootScroller set the outer viewport scroll layer in the compositor

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 52 matching lines @@
 class HitTestResult;
 class IntRect;
 class LocalFrame;
 class Node;
 class Page;
 class PaintArtifact;
 class PopupOpeningObserver;
 class WebDragData;
 class WebFrameScheduler;
 class WebImage;
+class WebLayer;
 
 struct CompositedSelection;
 struct DateTimeChooserParameters;
 struct FrameLoadRequest;
 struct GraphicsDeviceAdapter;
 struct ViewportDescription;
 struct WebPoint;
 struct WindowFeatures;
 
 class CORE_EXPORT ChromeClient : public HostWindow {
@@ skipping 176 matching lines @@
     virtual void didUpdateTextOfFocusedElementByNonUserInput() { }
     virtual void showImeIfNeeded() { }
 
     virtual void registerViewportLayers() const { }
 
     virtual void showUnhandledTapUIIfNeeded(IntPoint, Node*, bool) { }
 
     virtual void onMouseDown(Node*) { }
 
     virtual void didUpdateTopControls() const { }
+    virtual void didUpdateRootScrollerLayer(WebLayer*) const { }
 
     virtual void registerPopupOpeningObserver(PopupOpeningObserver*) = 0;
     virtual void unregisterPopupOpeningObserver(PopupOpeningObserver*) = 0;
 
     virtual CompositorProxyClient* createCompositorProxyClient(LocalFrame*) = 0;
 
     virtual FloatSize elasticOverscroll() const { return FloatSize(); }
 
     // Called when observed XHR, fetch, and other fetch request with non-GET
     // method is initiated from javascript. At this time, it is not guaranteed
@@ skipping 22 matching lines @@
 
     LayoutPoint m_lastToolTipPoint;
     String m_lastToolTipText;
 
     FRIEND_TEST_ALL_PREFIXES(ChromeClientTest, SetToolTipFlood);
 };
 
 } // namespace blink
 
 #endif // ChromeClient_h