if (ProcessCanceledCase(request))
nsresult status;  rv = request->GetStatus(&status);  NS_ASSERTION(NS_SUCCEEDED(rv), "Unable to get request status!"); if (NS_FAILED(rv)) return rv;  if (NS_FAILED(status)) {
NS_IMETHODIMP nsDocumentOpenInfo::OnStartRequest(nsIRequest *request, nsISupports * aCtxt){  nsresult rv = NS_OK;  //  // Deal with "special" HTTP responses:  //  // - In the case of a 204 (No Content) response, do not try to find a  //   content handler.  Just return.  This causes the request to be  //   ignored.  //  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(request, &rv));  if (NS_SUCCEEDED(rv)) {    PRUint32 responseCode = 0;    rv = httpChannel->GetResponseStatus(&responseCode);    if (NS_FAILED(rv)) {      // behave as in the canceled case      return NS_OK;    }    if (204 == responseCode) {      return NS_OK;    }  }  if (ProcessCanceledCase(request))    return NS_OK;  rv = DispatchContent(request, aCtxt);  if (m_targetStreamListener)    rv = m_targetStreamListener->OnStartRequest(request, aCtxt);  return rv;}