Oilpan: make DocumentFragment a heap allocated object.

Source/core/html/HTMLElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009 Apple Inc. All rights reserved.
  *
  * 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.
  *
@@ skipping 95 matching lines @@
     unsigned parseBorderWidthAttribute(const AtomicString&) const;
 
     virtual void childrenChanged(bool changedByParser = false, Node* beforeChange = 0, Node* afterChange = 0, int childCountDelta = 0) OVERRIDE;
     void calculateAndAdjustDirectionality();
 
 private:
     virtual String nodeName() const OVERRIDE FINAL;
 
     void mapLanguageAttributeToLocale(const AtomicString&, MutableStylePropertySet*);
 
-    PassRefPtr<DocumentFragment> textToFragment(const String&, ExceptionState&);
+    PassRefPtrWillBeRawPtr<DocumentFragment> textToFragment(const String&, ExceptionState&);
 
     void dirAttributeChanged(const AtomicString&);
     void adjustDirectionalityIfNeededAfterChildAttributeChanged(Element* child);
     void adjustDirectionalityIfNeededAfterChildrenChanged(Node* beforeChange, int childCountDelta);
     TextDirection directionality(Node** strongDirectionalityTextNode= 0) const;
 
     TranslateAttributeMode translateAttributeMode() const;
 
     void handleKeypressEvent(KeyboardEvent*);
 };
@@ skipping 23 matching lines @@
     template<typename T> inline bool is##thisType(const PassRefPtr<T>& node) { return is##thisType(node.get()); } \
     template<typename T> inline bool is##thisType(const RefPtr<T>& node) { return is##thisType(node.get()); } \
     template <> inline bool isElementOfType<const thisType>(const HTMLElement& element) { return is##thisType(element); } \
     DEFINE_ELEMENT_TYPE_CASTS_WITH_FUNCTION(thisType)
 
 } // namespace WebCore
 
 #include "HTMLElementTypeHelpers.h"
 
 #endif // HTMLElement_h