Implement CSSOM Smooth Scroll API

Source/core/frame/FrameView.h

Index: Source/core/frame/FrameView.h
diff --git a/Source/core/frame/FrameView.h b/Source/core/frame/FrameView.h
index ef3aa3aa986b65ff85f71ec2415d202970e33c80..234f0362c0023a742ba242b45175260cdebb71b4 100644
--- a/Source/core/frame/FrameView.h
+++ b/Source/core/frame/FrameView.h
@@ -72,6 +72,7 @@ public:
     virtual void setFrameRect(const IntRect&) OVERRIDE;
 
     virtual bool scheduleAnimation() OVERRIDE;
+    virtual void serviceScrollAnimations(double monotonicTime) OVERRIDE;
 
     LocalFrame& frame() const { return *m_frame; }
     Page* page() const;
@@ -151,7 +152,7 @@ public:
     virtual IntSize inputEventsOffsetForEmulation() const OVERRIDE;
     void setInputEventsTransformForEmulation(const IntSize&, float);
 
-    virtual void setScrollPosition(const IntPoint&) OVERRIDE;
+    virtual void setScrollPosition(const IntPoint&, ScrollBehavior = ScrollBehaviorInstant) OVERRIDE;
     virtual bool isRubberBandInProgress() const OVERRIDE;
     void setScrollPositionNonProgrammatically(const IntPoint&);
 
@@ -271,7 +272,9 @@ public:
 
     typedef HashSet<ScrollableArea*> ScrollableAreaSet;
     void addScrollableArea(ScrollableArea*);
+    bool addAnimatingScrollableArea(ScrollableArea*);
     void removeScrollableArea(ScrollableArea*);
+    bool removeAnimatingScrollableArea(ScrollableArea*);
     const ScrollableAreaSet* scrollableAreas() const { return m_scrollableAreas.get(); }
 
     // With CSS style "resize:" enabled, a little resizer handle will appear at the bottom
@@ -495,6 +498,7 @@ private:
     IntSize m_maxAutoSize;
 
     OwnPtr<ScrollableAreaSet> m_scrollableAreas;
+    OwnPtr<ScrollableAreaSet> m_animatingScrollableAreas;
     OwnPtr<ResizerAreaSet> m_resizerAreas;
     OwnPtr<ViewportConstrainedObjectSet> m_viewportConstrainedObjects;