Refactor wheel event handler registration in ScrollingCoordinator

Source/core/dom/WheelController.cpp

 /*
  * Copyright (C) 2013 Google, 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:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 51 matching lines @@
 static void wheelEventHandlerCountChanged(Document& document)
 {
     Page* page = document.page();
     if (!page)
         return;
 
     ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator();
     if (!scrollingCoordinator)
         return;
 
-    FrameView* frameView = document.view();
-    if (!frameView)
-        return;
-
-    scrollingCoordinator->frameViewWheelEventHandlerCountChanged(frameView);
+    scrollingCoordinator->updateHaveWheelEventHandlers();
 }
 
 void WheelController::didAddWheelEventHandler(Document& document)
 {
     ++m_wheelEventHandlerCount;
     Page* page = document.page();
     LocalFrame* mainFrame = page ? page->mainFrame() : 0;
     if (mainFrame)
         mainFrame->notifyChromeClientWheelEventHandlerCountChanged();
 
@@ skipping 26 matching lines @@
 {
     if (eventType != EventTypeNames::wheel && eventType != EventTypeNames::mousewheel)
         return;
 
     Document* document = window->document();
     ASSERT(document);
     didRemoveWheelEventHandler(*document);
 }
 
 } // namespace WebCore