This seems to occur across different configurations, and platforms.

Example on Linux:

https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_angle_rel_ng/985

Example on Windows:

https://ci.chromium.org/p/chromium/builders/luci.chromium.try/win_angle_rel_ng/697

Error text:

[5562:5562:0509/084724.017829:WARNING:gaia_auth_fetcher.cc(902)] Could not reach Google Accounts servers: errno -120

Traceback (most recent call last):
  _RunGpuTest at content/test/gpu/gpu_tests/gpu_integration_test.py:132
    self.RunActualGpuTest(url, *args)
  RunActualGpuTest at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:188
    getattr(self, test_name)(test_path, *args[1:])
  _RunConformanceTest at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:202
    self._CheckTestCompletion()
  _CheckTestCompletion at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:196
    'webglTestHarness._finished', timeout=self._GetTestTimeout())
  traced_function at third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
    return func(*args, **kwargs)
  WaitForJavaScriptCondition at third_party/catapult/telemetry/telemetry/internal/actions/action_runner.py:261
    return self._tab.WaitForJavaScriptCondition(*args, **kwargs)
  traced_function at third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
    return func(*args, **kwargs)
  WaitForJavaScriptCondition at third_party/catapult/telemetry/telemetry/internal/browser/web_contents.py:239
    return self._inspector_backend.WaitForJavaScriptCondition(*args, **kwargs)
  traced_function at third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
    return func(*args, **kwargs)
  WaitForJavaScriptCondition at third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py:302
    e.message + '\n' + debug_message)
TimeoutException: Timed out while waiting 300s for IsJavaScriptExpressionTrue.

CC'ing a few people who might be able to help triage this.