Part 1 of merges for Chromium bug #64589...

WebCore/page/ChromeClient.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple, Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 218 matching lines @@
         virtual void attachRootGraphicsLayer(Frame*, GraphicsLayer*) = 0;
         // Sets a flag to specify that the next time content is drawn to the window,
         // the changes appear on the screen in synchrony with updates to GraphicsLayers.
         virtual void setNeedsOneShotDrawingSynchronization() = 0;
         // Sets a flag to specify that the view needs to be updated, so we need
         // to do an eager layout before the drawing.
         virtual void scheduleCompositingLayerSync() = 0;
         // Returns whether or not the client can render the composited layer,
         // regardless of the settings.
         virtual bool allowsAcceleratedCompositing() const { return true; }
+
+        enum CompositingTrigger {
+            ThreeDTransformTrigger = 1 << 0,
+            VideoTrigger = 1 << 1,
+            PluginTrigger = 1 << 2,
+            CanvasTrigger = 1 << 3,
+            AnimationTrigger = 1 << 4,
+            AllTriggers = 0xFFFFFFFF
+        };
+        typedef unsigned CompositingTriggerFlags;
+
+        // Returns a bitfield indicating conditions that can trigger the compositor.
+        virtual CompositingTriggerFlags allowedCompositingTriggers() const { return static_cast<CompositingTriggerFlags>(AllTriggers); }
 #endif
 
         virtual bool supportsFullscreenForNode(const Node*) { return false; }
         virtual void enterFullscreenForNode(Node*) { }
         virtual void exitFullscreenForNode(Node*) { }
 
 #if ENABLE(FULLSCREEN_API)
         virtual bool supportsFullScreenForElement(const Element*) { return false; }
         virtual void enterFullScreenForElement(Element*) { }
         virtual void exitFullScreenForElement(Element*) { }
@@ skipping 30 matching lines @@
 
         virtual void postAccessibilityNotification(AccessibilityObject*, AXObjectCache::AXNotification) { }
 
     protected:
         virtual ~ChromeClient() { }
     };
 
 }
 
 #endif // ChromeClient_h