Allow cross-origin cssRules access to CORS-fetched stylesheet.

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 256 matching lines @@
     if (m_isInlineStylesheet)
         return true;
     KURL baseURL = m_contents->baseURL();
     if (baseURL.isEmpty())
         return true;
     Document* document = ownerDocument();
     if (!document)
         return true;
     if (document->securityOrigin()->canRequest(baseURL))
         return true;
+    if (m_allowRuleAccessFromOrigin && document->securityOrigin()->canAccess(m_allowRuleAccessFromOrigin.get()))
+        return true;
     return false;
 }
 
 PassRefPtrWillBeRawPtr<CSSRuleList> CSSStyleSheet::rules()
 {
     return cssRules();
 }
 
 unsigned CSSStyleSheet::insertRule(const String& ruleString, unsigned index, ExceptionState& exceptionState)
 {
@@ skipping 111 matching lines @@
 }
 
 Document* CSSStyleSheet::ownerDocument() const
 {
     const CSSStyleSheet* root = this;
     while (root->parentStyleSheet())
         root = root->parentStyleSheet();
     return root->ownerNode() ? &root->ownerNode()->document() : 0;
 }
 
+void CSSStyleSheet::setAllowRuleAccessFromOrigin(PassRefPtr<SecurityOrigin> allowedOrigin)
+{
+    m_allowRuleAccessFromOrigin = allowedOrigin;
+}
+
 void CSSStyleSheet::clearChildRuleCSSOMWrappers()
 {
     m_childRuleCSSOMWrappers.clear();
 }
 
 bool CSSStyleSheet::sheetLoaded()
 {
     ASSERT(m_ownerNode);
     setLoadCompleted(m_ownerNode->sheetLoaded());
     return m_loadCompleted;
@@ skipping 24 matching lines @@
     visitor->trace(m_mediaQueries);
     visitor->trace(m_ownerNode);
     visitor->trace(m_ownerRule);
     visitor->trace(m_mediaCSSOMWrapper);
     visitor->trace(m_childRuleCSSOMWrappers);
     visitor->trace(m_ruleListCSSOMWrapper);
     StyleSheet::trace(visitor);
 }
 
 } // namespace blink