Refactor wheel event handler registration in ScrollingCoordinator

Source/core/page/scrolling/ScrollingCoordinator.h

Index: Source/core/page/scrolling/ScrollingCoordinator.h
diff --git a/Source/core/page/scrolling/ScrollingCoordinator.h b/Source/core/page/scrolling/ScrollingCoordinator.h
index c5b661735de4343c97b4d8e11cce55a5c4ea72ac..92b9fb95e503a52988bdf96e3b3108e879c395d5 100644
--- a/Source/core/page/scrolling/ScrollingCoordinator.h
+++ b/Source/core/page/scrolling/ScrollingCoordinator.h
@@ -69,9 +69,8 @@ public:
 
     bool needsToUpdateAfterCompositingChange() const { return m_scrollGestureRegionIsDirty || m_touchEventTargetRectsAreDirty || frameViewIsDirty(); }
 
-    // Should be called whenever a wheel event handler is added or removed in the
-    // frame view's underlying document.
-    void frameViewWheelEventHandlerCountChanged(FrameView*);
+    void updateHaveWheelEventHandlers();
+    void updateHaveScrollEventHandlers();
 
     // Should be called whenever the slow repaint objects counter changes between zero and one.
     void frameViewHasSlowRepaintObjectsDidChange(FrameView*);
@@ -125,7 +124,6 @@ protected:
 
     bool isForMainFrame(ScrollableArea*) const;
 
-    unsigned computeCurrentWheelEventHandlerCount();
     GraphicsLayer* scrollLayerForFrameView(FrameView*);
     GraphicsLayer* counterScrollingLayerForFrameView(FrameView*);
 
@@ -137,7 +135,6 @@ protected:
     bool m_shouldScrollOnMainThreadDirty;
 
 private:
-    void recomputeWheelEventHandlerCountForFrameView(FrameView*);
     void setShouldUpdateScrollLayerPositionOnMainThread(MainThreadScrollingReasons);
 
     bool hasVisibleSlowRepaintViewportConstrainedObjects(FrameView*) const;
@@ -146,7 +143,6 @@ private:
     void setShouldHandleScrollGestureOnMainThreadRegion(const Region&);
     void setTouchEventTargetRects(LayerHitTestRects&);
     void computeTouchEventTargetRects(LayerHitTestRects&);
-    void setWheelEventHandlerCount(unsigned);
 
     blink::WebScrollbarLayer* addWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation, PassOwnPtr<blink::WebScrollbarLayer>);
     blink::WebScrollbarLayer* getWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation);