Remove frame flattening support as Chromium has no intention of using it

Source/core/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 73 matching lines @@
     LayoutUnit marginWidth() const { return m_margins.width(); } // -1 means default
     LayoutUnit marginHeight() const { return m_margins.height(); } // -1 means default
     void setMarginWidth(LayoutUnit);
     void setMarginHeight(LayoutUnit);
 
     virtual void setCanHaveScrollbars(bool);
     void updateCanHaveScrollbars();
 
     virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
 
-    virtual bool avoidScrollbarCreation() const;
-
     virtual void setContentsSize(const IntSize&);
 
     void layout(bool allowSubtree = true);
     bool didFirstLayout() const;
     void layoutTimerFired(Timer<FrameView>*);
     void scheduleRelayout();
     void scheduleRelayoutOfSubtree(RenderObject*);
     void unscheduleRelayout();
     bool layoutPending() const;
     bool isInLayout() const { return m_inLayout; }
@@ skipping 134 matching lines @@
     bool hasEverPainted() const { return m_lastPaintTime; }
     void setLastPaintTime(double lastPaintTime) { m_lastPaintTime = lastPaintTime; }
     void setNodeToDraw(Node*);
 
     virtual void paintOverhangAreas(GraphicsContext*, const IntRect& horizontalOverhangArea, const IntRect& verticalOverhangArea, const IntRect& dirtyRect);
     virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);
     virtual void paintScrollbar(GraphicsContext*, Scrollbar*, const IntRect&) OVERRIDE;
 
     Color documentBackgroundColor() const;
 
-    bool isInChildFrameWithFrameFlattening() const;
-
     static double currentPaintTimeStamp() { return sCurrentPaintTimeStamp; } // returns 0 if not painting
     
     void updateLayoutAndStyleIfNeededRecursive();
 
     void incrementVisuallyNonEmptyCharacterCount(unsigned);
     void incrementVisuallyNonEmptyPixelCount(const IntSize&);
     void setIsVisuallyNonEmpty() { m_isVisuallyNonEmpty = true; }
     bool isVisuallyNonEmpty() const { return m_isVisuallyNonEmpty; }
     void enableAutoSizeMode(bool enable, const IntSize& minSize, const IntSize& maxSize);
 
@@ skipping 173 matching lines @@
     void updateWidget(RenderObject*);
     void scrollToAnchor();
     void scrollPositionChanged();
 
     bool hasCustomScrollbars() const;
 
     virtual void updateScrollCorner();
 
     FrameView* parentFrameView() const;
 
-    bool doLayoutWithFrameFlattening(bool allowSubtree);
-
     virtual AXObjectCache* axObjectCache() const;
     void notifyWidgetsInAllFrames(WidgetNotification);
     void removeFromAXObjectCache();
     
     static double sCurrentPaintTimeStamp; // used for detecting decoded resource thrash in the cache
 
     LayoutSize m_size;
     LayoutSize m_margins;
     
     typedef HashSet<RenderObject*> RenderObjectSet;
@@ skipping 153 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