Optimize StyleSheetContents::checkLoaded by keeping track of completed

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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 121 matching lines @@
     bool wrapperInsertRule(PassRefPtrWillBeRawPtr<StyleRuleBase>, unsigned index);
     void wrapperDeleteRule(unsigned index);
 
     PassRefPtrWillBeRawPtr<StyleSheetContents> copy() const
     {
         return adoptRefWillBeNoop(new StyleSheetContents(*this));
     }
 
     void registerClient(CSSStyleSheet*);
     void unregisterClient(CSSStyleSheet*);
-    bool hasOneClient() { return m_clients.size() == 1; }
+    bool hasOneClient() { return (m_loadingClients.size() + m_completedClients.size()) == 1; }
+    void clientLoadCompleted(CSSStyleSheet*);
+    void clientLoadStarted(CSSStyleSheet*);
 
     bool isMutable() const { return m_isMutable; }
     void setMutable() { m_isMutable = true; }
 
     bool isInMemoryCache() const { return m_isInMemoryCache; }
     void addedToMemoryCache();
     void removedFromMemoryCache();
 
     void setHasMediaQueries();
     bool hasMediaQueries() { return m_hasMediaQueries; }
@@ skipping 25 matching lines @@
     bool m_hasSyntacticallyValidCSSHeader : 1;
     bool m_didLoadErrorOccur : 1;
     bool m_usesRemUnits : 1;
     bool m_isMutable : 1;
     bool m_isInMemoryCache : 1;
     bool m_hasFontFaceRule : 1;
     bool m_hasMediaQueries : 1;
 
     CSSParserContext m_parserContext;
 
-    WillBeHeapHashSet<RawPtrWillBeWeakMember<CSSStyleSheet> > m_clients;
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<CSSStyleSheet> > m_loadingClients;
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<CSSStyleSheet> > m_completedClients;
     typedef WillBeHeapHashSet<RawPtrWillBeWeakMember<CSSStyleSheet> >::iterator ClientsIterator;
 
     OwnPtrWillBeMember<RuleSet> m_ruleSet;
 };
 
 } // namespace
 
 #endif