What steps will reproduce the problem?
(1) create a local branch
(2) git cl patch 1377519
(3) blink_tool.py rebaseline-cl --patchset=6


2018-12-17 14:44:27,728 - Finished try jobs found for all try bots.
2018-12-17 14:44:46,361 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 10 seconds...
2018-12-17 14:44:56,586 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 15.0 seconds...
2018-12-17 14:45:11,734 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 22.5 seconds...
2018-12-17 14:45:34,377 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 33.75 seconds...
2018-12-17 14:46:08,295 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 50.625 seconds...
2018-12-17 14:46:59,101 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 75.9375 seconds...
2018-12-17 14:48:15,248 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 113.90625 seconds...
2018-12-17 14:50:09,399 - Received HTTP status 308 loading "https://test-results.appspot.com/data/layout_results/mac10_13-blink-rel/2357/retry_with_patch_summary.json".  Retrying in 170.859375 seconds...
Traceback (most recent call last):
  File "third_party/blink/tools/blink_tool.py", line 83, in <module>
    main()
  File "third_party/blink/tools/blink_tool.py", line 78, in main
    BlinkTool(os.path.abspath(__file__)).main()
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/tool/blink_tool.py", line 105, in main
    result = command.check_arguments_and_execute(options, args, self)
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/tool/commands/command.py", line 110, in check_arguments_and_execute
    return self.execute(options, args, tool) or 0
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/tool/commands/rebaseline_cl.py", line 138, in execute
    jobs_to_results, options.only_changed_tests)
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/tool/commands/rebaseline_cl.py", line 297, in _make_test_baseline_set
    builds_to_tests[build] = self._tests_to_rebaseline(build, results)
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/tool/commands/rebaseline_cl.py", line 338, in _tests_to_rebaseline
    new_failures = self._fetch_tests_with_new_failures(build)
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/tool/commands/rebaseline_cl.py", line 355, in _fetch_tests_with_new_failures
    content = buildbot.fetch_retry_summary_json(build)
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/common/memoized.py", line 45, in __call__
    result = self._function(*args)
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/common/net/buildbot.py", line 106, in fetch_retry_summary_json
    lambda: self.fetch_file('%s/%s' % (url_base, 'retry_with_patch_summary.json')))
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/common/net/network_transaction.py", line 61, in run
    self._check_for_timeout()
  File "/mnt/data/home/mali/src/chromium/src/third_party/blink/tools/blinkpy/common/net/network_transaction.py", line 68, in _check_for_timeout
    raise NetworkTimeout()
blinkpy.common.net.network_transaction.NetworkTimeout: NetworkTimeout