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

Source/core/css/CSSStyleSheet.cpp

Index: Source/core/css/CSSStyleSheet.cpp
diff --git a/Source/core/css/CSSStyleSheet.cpp b/Source/core/css/CSSStyleSheet.cpp
index 3434b1e155b0fc2bb94e8ab17450c94f84a2c62e..67a802e52314914d59b6dc05d263a9ab2db16998 100644
--- a/Source/core/css/CSSStyleSheet.cpp
+++ b/Source/core/css/CSSStyleSheet.cpp
@@ -274,6 +274,8 @@ bool CSSStyleSheet::canAccessRules() const
         return true;
     if (document->securityOrigin()->canRequest(baseURL))
         return true;
+    if (m_allowRuleAccessFromOrigin && document->securityOrigin()->canAccess(m_allowRuleAccessFromOrigin.get()))
+        return true;
     return false;
 }
 
@@ -405,6 +407,11 @@ Document* CSSStyleSheet::ownerDocument() const
     return root->ownerNode() ? &root->ownerNode()->document() : 0;
 }
 
+void CSSStyleSheet::setAllowRuleAccessFromOrigin(PassRefPtr<SecurityOrigin> allowedOrigin)
+{
+    m_allowRuleAccessFromOrigin = allowedOrigin;
+}
+
 void CSSStyleSheet::clearChildRuleCSSOMWrappers()
 {
     m_childRuleCSSOMWrappers.clear();