Introduce XMLHttpRequest.responseURL.

Source/core/xml/XMLHttpRequest.h

 /*
  *  Copyright (C) 2003, 2006, 2008 Apple Inc. All rights reserved.
  *  Copyright (C) 2005, 2006 Alexey Proskuryakov <ap@nypop.com>
  *  Copyright (C) 2011 Google Inc. All rights reserved.
  *  Copyright (C) 2012 Intel Corporation
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
@@ skipping 116 matching lines @@
 
     // Expose HTTP validation methods for other untrusted requests.
     static bool isAllowedHTTPMethod(const String&);
     static AtomicString uppercaseKnownHTTPMethod(const AtomicString&);
     static bool isAllowedHTTPHeader(const String&);
 
     void setResponseType(const String&, ExceptionState&);
     String responseType();
     ResponseTypeCode responseTypeCode() const { return m_responseTypeCode; }
 
+    String responseURL();
+
     // response attribute has custom getter.
     ArrayBuffer* responseArrayBuffer();
 
     void setLastSendLineNumber(unsigned lineNumber) { m_lastSendLineNumber = lineNumber; }
     void setLastSendURL(const String& url) { m_lastSendURL = url; }
 
     XMLHttpRequestUpload* upload();
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(readystatechange);
 
@@ skipping 109 matching lines @@
 
     // An enum corresponding to the allowed string values for the responseType attribute.
     ResponseTypeCode m_responseTypeCode;
     AsyncMethodRunner<XMLHttpRequest> m_dropProtectionRunner;
     RefPtr<SecurityOrigin> m_securityOrigin;
 };
 
 } // namespace WebCore
 
 #endif // XMLHttpRequest_h