Change CSSParserContext to have a Document handle (vs UseCounter).

third_party/WebKit/Source/core/css/StyleSheetContents.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2012 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 43 matching lines @@
   static StyleSheetContents* create(const String& originalURL,
                                     const CSSParserContext* context) {
     return new StyleSheetContents(0, originalURL, context);
   }
   static StyleSheetContents* create(StyleRuleImport* ownerRule,
                                     const String& originalURL,
                                     const CSSParserContext* context) {
     return new StyleSheetContents(ownerRule, originalURL, context);
   }
 
+  static const Document* singleOwnerDocument(const StyleSheetContents*);
+
   ~StyleSheetContents();
 
   const CSSParserContext* parserContext() const { return m_parserContext; }
 
   const AtomicString& defaultNamespace() { return m_defaultNamespace; }
   const AtomicString& namespaceURIFromPrefix(const AtomicString& prefix);
 
   void parseAuthorStyleSheet(const CSSStyleSheetResource*,
                              const SecurityOrigin*);
   void parseString(const String&);
@@ skipping 146 matching lines @@
   HeapHashSet<WeakMember<CSSStyleSheet>> m_loadingClients;
   HeapHashSet<WeakMember<CSSStyleSheet>> m_completedClients;
 
   Member<RuleSet> m_ruleSet;
   String m_sourceMapURL;
 };
 
 }  // namespace blink
 
 #endif