[oilpan] Completely move HTMLFormControlElement's hierarchy to the managed heap

Source/core/accessibility/AccessibilitySlider.h

 /*
  * Copyright (C) 2009 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
@@ skipping 28 matching lines @@
 class AccessibilitySlider : public AccessibilityRenderObject {
     
 public:
     static PassRefPtr<AccessibilitySlider> create(RenderObject*);
     virtual ~AccessibilitySlider() { }
 
 protected:
     explicit AccessibilitySlider(RenderObject*);
 
 private:
-    HTMLInputElement* element() const;
+    Result<HTMLInputElement> element() const;
     virtual AccessibilityObject* elementAccessibilityHitTest(const IntPoint&) const;
 
     virtual AccessibilityRole roleValue() const { return SliderRole; }    
     virtual bool isSlider() const { return true; }
     virtual bool isInputSlider() const { return true; }
     virtual bool isControl() const { return true; }
     
     virtual void addChildren();
     
     virtual bool canSetValueAttribute() const { return true; }
@@ skipping 19 matching lines @@
 private:
     AccessibilitySliderThumb();
 
     virtual bool computeAccessibilityIsIgnored() const;
 };
 
 
 } // namespace WebCore
 
 #endif // AccessibilitySlider_h