Oilpan: add [WillBeGarbageCollected] for Element.

Source/core/dom/SelectorQuery.h

 /*
  * Copyright (C) 2011, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. 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.
@@ skipping 32 matching lines @@
 class Node;
 class NodeList;
 class SimpleNodeList;
 class SpaceSplitString;
 
 class SelectorDataList {
 public:
     void initialize(const CSSSelectorList&);
     bool matches(Element&) const;
     PassRefPtrWillBeRawPtr<NodeList> queryAll(ContainerNode& rootNode) const;
-    PassRefPtr<Element> queryFirst(ContainerNode& rootNode) const;
+    PassRefPtrWillBeRawPtr<Element> queryFirst(ContainerNode& rootNode) const;
 
 private:
     bool canUseFastQuery(const ContainerNode& rootNode) const;
     bool selectorMatches(const CSSSelector&, Element&, const ContainerNode&) const;
 
     template <typename SelectorQueryTrait>
     void collectElementsByClassName(ContainerNode& rootNode, const AtomicString& className, typename SelectorQueryTrait::OutputType&) const;
     template <typename SelectorQueryTrait>
     void collectElementsByTagName(ContainerNode& rootNode, const QualifiedName& tagName, typename SelectorQueryTrait::OutputType&) const;
 
@@ skipping 20 matching lines @@
     bool m_crossesTreeBoundary;
 };
 
 class SelectorQuery {
     WTF_MAKE_NONCOPYABLE(SelectorQuery);
     WTF_MAKE_FAST_ALLOCATED;
 public:
     explicit SelectorQuery(const CSSSelectorList&);
     bool matches(Element&) const;
     PassRefPtrWillBeRawPtr<NodeList> queryAll(ContainerNode& rootNode) const;
-    PassRefPtr<Element> queryFirst(ContainerNode& rootNode) const;
+    PassRefPtrWillBeRawPtr<Element> queryFirst(ContainerNode& rootNode) const;
 private:
     SelectorDataList m_selectors;
     CSSSelectorList m_selectorList;
 };
 
 class SelectorQueryCache {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     SelectorQuery* add(const AtomicString&, const Document&, ExceptionState&);
     void invalidate();
 
 private:
     HashMap<AtomicString, OwnPtr<SelectorQuery> > m_entries;
 };
 
 }
 
 #endif