Move iframe and plugin compositing triggers into additionalCompositingReasons

Source/core/rendering/RenderEmbeddedObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  *           (C) 2000 Stefan Schimanski (1Stein@gmx.de)
  * Copyright (C) 2004, 2005, 2006, 2008, 2009, 2010 Apple Inc. 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 228 matching lines @@
 bool RenderEmbeddedObject::scroll(ScrollDirection direction, ScrollGranularity granularity, float)
 {
     return false;
 }
 
 bool RenderEmbeddedObject::canHaveChildren() const
 {
     return false;
 }
 
+CompositingReasons RenderEmbeddedObject::additionalCompositingReasons(CompositingTriggerFlags triggers) const
+{
+    if ((triggers & PluginTrigger) && requiresAcceleratedCompositing())
+        return CompositingReasonPlugin;
+    return CompositingReasonNone;
 }
+
+}