Use weak members to cache StyleSheetContents.

third_party/WebKit/Source/core/dom/StyleElement.h

 /*
  * Copyright (C) 2006, 2007 Rob Buis
  *
  * 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 13 matching lines @@
 #include "core/css/CSSStyleSheet.h"
 #include "core/dom/StyleEngineContext.h"
 #include "wtf/text/TextPosition.h"
 
 namespace blink {
 
 class ContainerNode;
 class Document;
 class Element;
 
-class StyleElement : public GarbageCollectedMixin {
+class CORE_EXPORT StyleElement : public GarbageCollectedMixin {
 public:
     StyleElement(Document*, bool createdByParser);
     virtual ~StyleElement();
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     enum ProcessingResult {
         ProcessingSuccessful,
         ProcessingFatalError
     };
@@ skipping 24 matching lines @@
     bool m_createdByParser : 1;
     bool m_loading : 1;
     bool m_registeredAsCandidate : 1;
     TextPosition m_startPosition;
     StyleEngineContext m_styleEngineContext;
 };
 
 } // namespace blink
 
 #endif