Add support for accelerated fixed root background

Source/WebCore/page/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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
@@ skipping 199 matching lines @@
     void removeSlowRepaintObject();
     bool hasSlowRepaintObjects() const { return m_slowRepaintObjectCount; }
 
     // Includes fixed- and sticky-position objects.
     typedef HashSet<RenderObject*> ViewportConstrainedObjectSet;
     void addViewportConstrainedObject(RenderObject*);
     void removeViewportConstrainedObject(RenderObject*);
     const ViewportConstrainedObjectSet* viewportConstrainedObjects() const { return m_viewportConstrainedObjects.get(); }
     bool hasViewportConstrainedObjects() const { return m_viewportConstrainedObjects && m_viewportConstrainedObjects->size() > 0; }
 
+    void setHasFixedRootBackgroundLayer(bool hasLayer) { m_hasFixedRootBackgroundLayer = hasLayer; }
+    bool hasFixedRootBackgroundLayer() const { return m_hasFixedRootBackgroundLayer; }
+
     // Functions for querying the current scrolled position, negating the effects of overhang
     // and adjusting for page scale.
     IntSize scrollOffsetForFixedPosition() const;
     // Static function can be called from another thread.
     static IntSize scrollOffsetForFixedPosition(const IntRect& visibleContentRect, const IntSize& totalContentsSize, const IntPoint& scrollPosition, const IntPoint& scrollOrigin, float frameScaleFactor, bool fixedElementsLayoutRelativeToFrame, int headerHeight, int footerHeight);
 
     bool fixedElementsLayoutRelativeToFrame() const;
 
     void beginDeferredRepaints();
     void endDeferredRepaints();
@@ skipping 360 matching lines @@
     bool m_inAutoSize;
     // True if autosize has been run since m_shouldAutoSize was set.
     bool m_didRunAutosize;
     // The lower bound on the size when autosizing.
     IntSize m_minAutoSize;
     // The upper bound on the size when autosizing.
     IntSize m_maxAutoSize;
 
     OwnPtr<ScrollableAreaSet> m_scrollableAreas;
     OwnPtr<ViewportConstrainedObjectSet> m_viewportConstrainedObjects;
+    bool m_hasFixedRootBackgroundLayer;
 
     int m_headerHeight;
     int m_footerHeight;
 
     static double s_normalDeferredRepaintDelay;
     static double s_initialDeferredRepaintDelayDuringLoading;
     static double s_maxDeferredRepaintDelayDuringLoading;
     static double s_deferredRepaintDelayIncrementDuringLoading;
 
 #if ENABLE(CSS_FILTERS)
@@ skipping 50 matching lines @@
     ASSERT(!widget || widget->isFrameView());
     return static_cast<const FrameView*>(widget);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toFrameView(const FrameView*);
 
 } // namespace WebCore
 
 #endif // FrameView_h