[Oilpan]: Make ElementResolveContext and SharedStyleFinder STACK_ALLOCATED.

Source/core/css/resolver/SharedStyleFinder.h

 /*
  * Copyright (C) 2013 Google, Inc.
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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 18 matching lines @@
 
 class Element;
 class Node;
 class RenderStyle;
 class RuleFeatureSet;
 class RuleSet;
 class SpaceSplitString;
 class StyleResolver;
 
 class SharedStyleFinder {
+    STACK_ALLOCATED();
 public:
     // RuleSets are passed non-const as the act of matching against them can cause them
     // to be compacted. :(
     SharedStyleFinder(const ElementResolveContext& context,
         const RuleFeatureSet& features, RuleSet* siblingRuleSet,
         RuleSet* uncommonAttributeRuleSet, StyleResolver& styleResolver)
         : m_elementAffectedByClassRules(false)
         , m_features(features)
         , m_siblingRuleSet(siblingRuleSet)
         , m_uncommonAttributeRuleSet(uncommonAttributeRuleSet)
@@ skipping 16 matching lines @@
     bool sharingCandidateHasIdenticalStyleAffectingAttributes(Element& candidate) const;
     bool sharingCandidateShadowHasSharedStyleSheetContents(Element& candidate) const;
     bool sharingCandidateDistributedToSameInsertionPoint(Element& candidate) const;
     bool matchesRuleSet(RuleSet*);
 
     Element& element() const { return *m_context.element(); }
     Document& document() const { return element().document(); }
 
     bool m_elementAffectedByClassRules;
     const RuleFeatureSet& m_features;
-    RuleSet* m_siblingRuleSet;
-    RuleSet* m_uncommonAttributeRuleSet;
+    RawPtrWillBeMember<RuleSet> m_siblingRuleSet;
+    RawPtrWillBeMember<RuleSet> m_uncommonAttributeRuleSet;
     StyleResolver& m_styleResolver;
     const ElementResolveContext& m_context;
 };
 
 } // namespace WebCore
 
 #endif // SharedStyleFinder_h