Oilpan: Allocate all EventTarget derived types on the manged heap.

Source/core/dom/ElementRareData.h

 /*
  * Copyright (C) 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Smith <catfish.man@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 113 matching lines @@
 
 private:
     short m_tabindex;
 
     IntSize m_savedLayerScrollOffset;
 
     OwnPtrWillBeMember<DatasetDOMStringMap> m_dataset;
     OwnPtrWillBeMember<ClassList> m_classList;
     OwnPtrWillBeMember<ElementShadow> m_shadow;
     OwnPtrWillBeMember<NamedNodeMap> m_attributeMap;
-    OwnPtr<InputMethodContext> m_inputMethodContext;
+    OwnPtrWillBeMember<InputMethodContext> m_inputMethodContext;
     OwnPtrWillBeMember<ActiveAnimations> m_activeAnimations;
     OwnPtrWillBeMember<InlineCSSStyleDeclaration> m_cssomWrapper;
 
     RefPtr<RenderStyle> m_computedStyle;
     RefPtr<CustomElementDefinition> m_customElementDefinition;
 
     RefPtrWillBeMember<PseudoElement> m_generatedBefore;
     RefPtrWillBeMember<PseudoElement> m_generatedAfter;
     RefPtrWillBeMember<PseudoElement> m_backdrop;
 
@@ skipping 67 matching lines @@
 }
 
 inline void ElementRareData::resetStyleState()
 {
     clearElementFlag(StyleAffectedByEmpty);
 }
 
 } // namespace
 
 #endif // ElementRareData_h