Replace responseType mismatch handling code in XMLHttpRequest::responseJSONSource() with ASSERT

Source/core/xml/XMLHttpRequest.cpp

 /*
  *  Copyright (C) 2004, 2006, 2008 Apple Inc. All rights reserved.
  *  Copyright (C) 2005-2007 Alexey Proskuryakov <ap@webkit.org>
  *  Copyright (C) 2007, 2008 Julien Chaffraix <jchaffraix@webkit.org>
  *  Copyright (C) 2008, 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
@@ skipping 206 matching lines @@
 {
     if (m_responseTypeCode != ResponseTypeDefault && m_responseTypeCode != ResponseTypeText) {
         es.throwDOMException(InvalidStateError, ExceptionMessages::failedToGet("responseText", "XMLHttpRequest", "the value is only accessible if the object's 'responseType' is '' or 'text' (was '" + responseType() + "')."));
         return ScriptString();
     }
     if (m_error || (m_state != LOADING && m_state != DONE))
         return ScriptString();
     return m_responseText;
 }
 
-ScriptString XMLHttpRequest::responseJSONSource(ExceptionState& es)
+ScriptString XMLHttpRequest::responseJSONSource()
 {
-    if (m_responseTypeCode != ResponseTypeJSON) {
-        es.throwDOMException(InvalidStateError);
-        return ScriptString();
-    }
+    ASSERT(m_responseTypeCode == ResponseTypeJSON);
+
     if (m_error || m_state != DONE)
         return ScriptString();
     return m_responseText;
 }
 
 Document* XMLHttpRequest::responseXML(ExceptionState& es)
 {
     if (m_responseTypeCode != ResponseTypeDefault && m_responseTypeCode != ResponseTypeDocument) {
         es.throwDOMException(InvalidStateError, ExceptionMessages::failedToGet("responseXML", "XMLHttpRequest", "the value is only accessible if the object's 'responseType' is '' or 'document' (was '" + responseType() + "')."));
         return 0;
@@ skipping 1016 matching lines @@
 {
     return eventNames().interfaceForXMLHttpRequest;
 }
 
 ScriptExecutionContext* XMLHttpRequest::scriptExecutionContext() const
 {
     return ActiveDOMObject::scriptExecutionContext();
 }
 
 } // namespace WebCore