XMLHttpRequest::overrideMimeType should throw InvalidStateError

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 1015 matching lines @@
     }
 
     // Note: The below event dispatch may be called while |hasPendingActivity() == false|,
     // when |handleRequestError| is called after |internalAbort()|.
     // This is safe, however, as |this| will be kept alive from a strong ref |Event::m_target|.
     dispatchProgressEvent(EventTypeNames::progress, receivedLength, expectedLength);
     dispatchProgressEvent(type, receivedLength, expectedLength);
     dispatchProgressEvent(EventTypeNames::loadend, receivedLength, expectedLength);
 }
 
-void XMLHttpRequest::overrideMimeType(const AtomicString& override)
+void XMLHttpRequest::overrideMimeType(const AtomicString& mimeType, ExceptionState& exceptionState)
 {
-    // FIXME: This method must throw an InvalidStateError exception when the
-    // XHR is in the LOADING or DONE state. http://crbug.com/402375
+    if (m_state == LOADING || m_state == DONE) {
+        exceptionState.throwDOMException(InvalidStateError, "MimeType cannot be overridden when the state is LOADING or DONE.");
+        return;
+    }
 
-    m_mimeTypeOverride = override;
+    m_mimeTypeOverride = mimeType;
 }
 
 void XMLHttpRequest::setRequestHeader(const AtomicString& name, const AtomicString& value, ExceptionState& exceptionState)
 {
     if (m_state != OPENED || m_loader) {
         exceptionState.throwDOMException(InvalidStateError, "The object's state must be OPENED.");
         return;
     }
 
     if (!isValidHTTPToken(name)) {
@@ skipping 366 matching lines @@
 {
     visitor->trace(m_responseBlob);
     visitor->trace(m_responseStream);
     visitor->trace(m_responseDocument);
     visitor->trace(m_progressEventThrottle);
     visitor->trace(m_upload);
     XMLHttpRequestEventTarget::trace(visitor);
 }
 
 } // namespace blink