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

Source/core/accessibility/AccessibilitySlider.cpp

 /*
  * 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 109 matching lines @@
     return static_cast<float>(element()->maximum());
 }
 
 float AccessibilitySlider::minValueForRange() const
 {
     return static_cast<float>(element()->minimum());
 }
 
 void AccessibilitySlider::setValue(const String& value)
 {
-    HTMLInputElement* input = element();
+    Handle<HTMLInputElement> input = element();
     
     if (input->value() == value)
         return;
 
     input->setValue(value);
 
     // Fire change event manually, as RenderSlider::setValueForPosition does.
     input->dispatchFormControlChangeEvent();
 }
 
-HTMLInputElement* AccessibilitySlider::element() const
+Result<HTMLInputElement> AccessibilitySlider::element() const
 {
-    return static_cast<HTMLInputElement*>(m_renderer->node());
+    return Handle<HTMLInputElement>(static_cast<HTMLInputElement*>(m_renderer->node()));
 }
 
 
 AccessibilitySliderThumb::AccessibilitySliderThumb()
 {
 }
 
 PassRefPtr<AccessibilitySliderThumb> AccessibilitySliderThumb::create()
 {
     return adoptRef(new AccessibilitySliderThumb());
 }
     
 LayoutRect AccessibilitySliderThumb::elementRect() const
 {
     if (!m_parent)
         return LayoutRect();
     
     RenderObject* sliderRenderer = m_parent->renderer();
     if (!sliderRenderer || !sliderRenderer->isSlider())
         return LayoutRect();
     return sliderThumbElementOf(sliderRenderer->node())->boundingBox();
 }
 
 bool AccessibilitySliderThumb::computeAccessibilityIsIgnored() const
 {
     return accessibilityIsIgnoredByDefault();
 }
 
 } // namespace WebCore