If you upload a change to the new gerrit review system you will get this error :

alexi@ALEXIS-DESKTOP 10:19:57:~/Development/chromium/src/tools/gyp$ git cl upload
Using 50% similarity for rename/copy detection. Override with --similarity.
Traceback (most recent call last):
  File "C:\Users\alexi\Development\depot_tools\\git_cl.py", line 5699, in <module>
    sys.exit(main(sys.argv[1:]))
  File "C:\Users\alexi\Development\depot_tools\\git_cl.py", line 5681, in main
    return dispatcher.execute(OptionParser(), argv)
  File "C:\Users\alexi\Development\depot_tools\subcommand.py", line 252, in execute
    return command(parser, args[1:])
  File "C:\Users\alexi\Development\depot_tools\\git_cl.py", line 4667, in CMDupload
    return cl.CMDUpload(options, args, orig_args)
  File "C:\Users\alexi\Development\depot_tools\\git_cl.py", line 1556, in CMDUpload
    self._codereview_impl.EnsureCanUploadPatchset()
  File "C:\Users\alexi\Development\depot_tools\\git_cl.py", line 2411, in EnsureCanUploadPatchset
    self.FetchDescription()
  File "C:\Users\alexi\Development\depot_tools\\git_cl.py", line 2512, in FetchDescription
    no_cache=force)
  File "C:\Users\alexi\Development\depot_tools\\git_cl.py", line 2605, in _GetChangeDetail
    options, ignore_404=False)
  File "C:\Users\alexi\Development\depot_tools\gerrit_util.py", line 532, in GetChangeDetail
    return ReadHttpJsonResponse(CreateHttpConn(host, path), ignore_404=ignore_404)
  File "C:\Users\alexi\Development\depot_tools\gerrit_util.py", line 314, in CreateHttpConn
    conn.request(**conn.req_params)
  File "C:\Users\alexi\Development\depot_tools\python276_bin\lib\httplib.py", line 973, in request
    self._send_request(method, url, body, headers)
  File "C:\Users\alexi\Development\depot_tools\python276_bin\lib\httplib.py", line 1007, in _send_request
    self.endheaders(body)
  File "C:\Users\alexi\Development\depot_tools\python276_bin\lib\httplib.py", line 969, in endheaders
    self._send_output(message_body)
  File "C:\Users\alexi\Development\depot_tools\python276_bin\lib\httplib.py", line 829, in _send_output
    self.send(msg)
  File "C:\Users\alexi\Development\depot_tools\python276_bin\lib\httplib.py", line 791, in send
    self.connect()
  File "C:\Users\alexi\Development\depot_tools\python276_bin\lib\httplib.py", line 1172, in connect
    self.timeout, self.source_address)
  File "C:\Users\alexi\Development\depot_tools\python276_bin\lib\socket.py", line 571, in create_connection
    raise err
socket.error: [Errno 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

Note that the old tool (like rietvield) works just fine and my proxy is correctly setup. We at Intel have all of our traffic behind proxy.