Remove Scrollbar dependency on AXObjectCache

Source/core/platform/Scrollbar.h

 /*
  * Copyright (C) 2004, 2006 Apple Computer, 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 17 matching lines @@
 
 #include "platform/Timer.h"
 #include "platform/Widget.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "platform/scroll/ScrollbarThemeClient.h"
 #include "wtf/MathExtras.h"
 #include "wtf/PassRefPtr.h"
 
 namespace WebCore {
 
-class AXObjectCache;
 class GraphicsContext;
 class IntRect;
 class PlatformGestureEvent;
 class PlatformMouseEvent;
 class ScrollableArea;
 class ScrollbarTheme;
 class ScrollView;
 
 class Scrollbar : public Widget,
                   public ScrollbarThemeClient {
@@ skipping 137 matching lines @@
 
     Timer<Scrollbar> m_scrollTimer;
     bool m_overlapsResizer;
 
     bool m_suppressInvalidation;
 
     bool m_isAlphaLocked;
 
 private:
     virtual bool isScrollbar() const { return true; }
-    virtual AXObjectCache* existingAXObjectCache() const;
 
     float scrollableAreaCurrentPos() const;
 };
 
 inline Scrollbar* toScrollbar(Widget* widget)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!widget || widget->isScrollbar());
     return static_cast<Scrollbar*>(widget);
 }
 
 inline const Scrollbar* toScrollbar(const Widget* widget)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!widget || widget->isScrollbar());
     return static_cast<const Scrollbar*>(widget);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toScrollbar(const Scrollbar*);
 
 } // namespace WebCore
 
 #endif // Scrollbar_h