Optimize StyleSheetContents::checkLoaded by keeping track of completed

Source/core/css/CSSStyleSheet.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 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 398 matching lines @@
 }
 
 void CSSStyleSheet::clearChildRuleCSSOMWrappers()
 {
     m_childRuleCSSOMWrappers.clear();
 }
 
 bool CSSStyleSheet::sheetLoaded()
 {
     ASSERT(m_ownerNode);
-    m_loadCompleted = m_ownerNode->sheetLoaded();
+    setLoadCompleted(m_ownerNode->sheetLoaded());
     return m_loadCompleted;
 }
 
 void CSSStyleSheet::startLoadingDynamicSheet()
 {
-    m_loadCompleted = false;
+    setLoadCompleted(false);
     m_ownerNode->startLoadingDynamicSheet();
 }
 
+void CSSStyleSheet::setLoadCompleted(bool completed)
+{
+    if (completed == m_loadCompleted)
+        return;
+
+    m_loadCompleted = completed;
+
+    if (completed)
+        m_contents->clientLoadCompleted(this);
+    else
+        m_contents->clientLoadStarted(this);
+}
+
 void CSSStyleSheet::trace(Visitor* visitor)
 {
     visitor->trace(m_contents);
     visitor->trace(m_mediaQueries);
     visitor->trace(m_ownerRule);
     visitor->trace(m_mediaCSSOMWrapper);
     visitor->trace(m_childRuleCSSOMWrappers);
     visitor->trace(m_ruleListCSSOMWrapper);
 }
 
 }