Delay scrollContents until the next paint

Source/core/frame/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 133 matching lines @@
     virtual IntRect windowResizerRect() const OVERRIDE;
 
     virtual float visibleContentScaleFactor() const OVERRIDE { return m_visibleContentScaleFactor; }
     void setVisibleContentScaleFactor(float);
 
     virtual float inputEventsScaleFactor() const OVERRIDE;
     virtual IntSize inputEventsOffsetForEmulation() const OVERRIDE;
     void setInputEventsTransformForEmulation(const IntSize&, float);
 
     virtual void setScrollPosition(const IntPoint&) OVERRIDE;
-    virtual void repaintFixedElementsAfterScrolling() OVERRIDE;
-    virtual void updateFixedElementsAfterScrolling() OVERRIDE;
     virtual bool shouldRubberBandInDirection(ScrollDirection) const OVERRIDE;
     virtual bool isRubberBandInProgress() const OVERRIDE;
     void setScrollPositionNonProgrammatically(const IntPoint&);
 
     // This is different than visibleContentRect() in that it ignores negative (or overly positive)
     // offsets from rubber-banding, and it takes zooming into account.
     LayoutRect viewportConstrainedVisibleContentRect() const;
     void viewportConstrainedVisibleContentSizeChanged(bool widthChanged, bool heightChanged);
 
     AtomicString mediaType() const;
@@ skipping 158 matching lines @@
     virtual void scrollTo(const IntSize&) OVERRIDE;
     virtual IntRect scrollableAreaBoundingBox() const OVERRIDE;
     virtual bool scrollAnimatorEnabled() const OVERRIDE;
     virtual bool usesCompositedScrolling() const OVERRIDE;
     virtual GraphicsLayer* layerForScrolling() const OVERRIDE;
     virtual GraphicsLayer* layerForHorizontalScrollbar() const OVERRIDE;
     virtual GraphicsLayer* layerForVerticalScrollbar() const OVERRIDE;
     virtual GraphicsLayer* layerForScrollCorner() const OVERRIDE;
 
 protected:
+    virtual void scrollContentsIfNeeded();
     virtual bool scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect) OVERRIDE;
     virtual void scrollContentsSlowPath(const IntRect& updateRect) OVERRIDE;
 
     virtual bool isVerticalDocument() const OVERRIDE;
     virtual bool isFlippedDocument() const OVERRIDE;
 
 private:
     explicit FrameView(LocalFrame*);
 
     void reset();
@@ skipping 43 matching lines @@
     virtual void notifyPageThatContentAreaWillPaint() const OVERRIDE;
 
     void scheduleUpdateWidgetsIfNecessary();
     void updateWidgetsTimerFired(Timer<FrameView>*);
     bool updateWidgets();
 
     void scrollToAnchor();
     void scrollPositionChanged();
     void didScrollTimerFired(Timer<FrameView>*);
 
+    void updateLayersAndCompositingAfterScrollIfNeeded();
+    void updateFixedElementRepaintRectsAfterScroll();
+
     bool hasCustomScrollbars() const;
     bool shouldUseCustomScrollbars(Element*& customScrollbarElement, LocalFrame*& customScrollbarFrame);
 
     virtual void updateScrollCorner() OVERRIDE;
 
     FrameView* parentFrameView() const;
 
     AXObjectCache* axObjectCache() const;
     void removeFromAXObjectCache();
 
@@ skipping 154 matching lines @@
         m_view->setCanRepaintDuringPerformLayout(m_originalValue);
     }
 private:
     FrameView* m_view;
     bool m_originalValue;
 };
 
 } // namespace WebCore
 
 #endif // FrameView_h