Disentangle updating the ScrollingCoordinator from RenderLayerCompositor

Source/core/page/scrolling/ScrollingCoordinator.h

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 46 matching lines @@
     static PassOwnPtr<ScrollingCoordinator> create(Page*);
 
     void willBeDestroyed();
 
     // Return whether this scrolling coordinator handles scrolling for the given frame view.
     bool coordinatesScrollingForFrameView(FrameView*) const;
 
     // Called when any frame has done its layout.
     void notifyLayoutUpdated();
 
-    // Should be called after compositing has been updated.
-    void updateAfterCompositingChange();
-
-    bool needsToUpdateAfterCompositingChange() const { return m_scrollGestureRegionIsDirty || m_touchEventTargetRectsAreDirty || frameViewIsDirty(); }
+    void updateAfterCompositingChangeIfNeeded();
 
     void updateHaveWheelEventHandlers();
     void updateHaveScrollEventHandlers();
 
     // Should be called whenever the slow repaint objects counter changes between zero and one.
     void frameViewHasSlowRepaintObjectsDidChange(FrameView*);
 
     // Should be called whenever the set of fixed objects changes.
     void frameViewFixedObjectsDidChange(FrameView*);
 
@@ skipping 44 matching lines @@
     bool isForMainFrame(ScrollableArea*) const;
 
     Page* m_page;
 
     // Dirty flags used to idenfity what really needs to be computed after compositing is updated.
     bool m_scrollGestureRegionIsDirty;
     bool m_touchEventTargetRectsAreDirty;
     bool m_shouldScrollOnMainThreadDirty;
 
 private:
+    bool shouldUpdateAfterCompositingChange() const { return m_scrollGestureRegionIsDirty || m_touchEventTargetRectsAreDirty || frameViewIsDirty(); }
+
     void setShouldUpdateScrollLayerPositionOnMainThread(MainThreadScrollingReasons);
 
     bool hasVisibleSlowRepaintViewportConstrainedObjects(FrameView*) const;
 
     bool touchHitTestingEnabled() const;
     void setShouldHandleScrollGestureOnMainThreadRegion(const Region&);
     void setTouchEventTargetRects(LayerHitTestRects&);
     void computeTouchEventTargetRects(LayerHitTestRects&);
 
     blink::WebScrollbarLayer* addWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation, PassOwnPtr<blink::WebScrollbarLayer>);
     blink::WebScrollbarLayer* getWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation);
     void removeWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation);
 
     bool frameViewIsDirty() const;
 
     typedef HashMap<ScrollableArea*, OwnPtr<blink::WebScrollbarLayer> > ScrollbarMap;
     ScrollbarMap m_horizontalScrollbars;
     ScrollbarMap m_verticalScrollbars;
     HashSet<const RenderLayer*> m_layersWithTouchRects;
     bool m_wasFrameScrollable;
 
     // This is retained for testing.
     MainThreadScrollingReasons m_lastMainThreadScrollingReasons;
 };
 
 } // namespace WebCore
 
 #endif // ScrollingCoordinator_h