Do not keep InvalidationSets on the Oilpan heap.

third_party/WebKit/Source/core/css/resolver/StyleResolver.h

 /*
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 64 matching lines @@
 
 const unsigned styleSharingListSize = 15;
 const unsigned styleSharingMaxDepth = 32;
 using StyleSharingList = WillBeHeapDeque<RawPtrWillBeMember<Element>, styleSharingListSize>;
 using ActiveInterpolationsMap = HashMap<PropertyHandle, Vector<RefPtr<Interpolation>, 1>>;
 
 // This class selects a ComputedStyle for a given element based on a collection of stylesheets.
 class CORE_EXPORT StyleResolver final : public NoBaseWillBeGarbageCollectedFinalized<StyleResolver> {
     WTF_MAKE_NONCOPYABLE(StyleResolver); WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(StyleResolver);
 public:
-    explicit StyleResolver(Document&);
-    virtual ~StyleResolver();
+    static PassOwnPtrWillBeRawPtr<StyleResolver> create(Document& document)
+    {
+        return adoptPtrWillBeNoop(new StyleResolver(document));
+    }
+    ~StyleResolver();
 
     // FIXME: StyleResolver should not be keeping tree-walk state.
     // These should move to some global tree-walk state, or should be contained in a
     // TreeWalkContext or similar which is passed in to StyleResolver methods when available.
     // Using these during tree walk will allow style selector to optimize child and descendant selector lookups.
     void pushParentElement(Element&);
     void popParentElement(Element&);
 
     PassRefPtr<ComputedStyle> styleForElement(Element*, const ComputedStyle* parentStyle = 0, StyleSharingBehavior = AllowStyleSharing,
         RuleMatchingBehavior = MatchAllRules);
@@ skipping 81 matching lines @@
     void increaseStyleSharingDepth() { ++m_styleSharingDepth; }
     void decreaseStyleSharingDepth() { --m_styleSharingDepth; }
 
     PassRefPtrWillBeRawPtr<PseudoElement> createPseudoElementIfNeeded(Element& parent, PseudoId);
 
     DECLARE_TRACE();
 
     void addTreeBoundaryCrossingScope(ContainerNode& scope);
 
 private:
+    explicit StyleResolver(Document&);
+
     PassRefPtr<ComputedStyle> initialStyleForElement();
 
     void initWatchedSelectorRules();
 
     // FIXME: This should probably go away, folded into FontBuilder.
     void updateFont(StyleResolverState&);
 
     void loadPendingResources(StyleResolverState&);
     void adjustComputedStyle(StyleResolverState&, Element*);
 
@@ skipping 60 matching lines @@
 
     OwnPtr<StyleResolverStats> m_styleResolverStats;
 
     // Use only for Internals::updateStyleAndReturnAffectedElementCount.
     unsigned m_accessCount;
 };
 
 } // namespace blink
 
 #endif // StyleResolver_h