https://console.developers.google.com/m/cloudstorage/b/chrome-telemetry-output/o/d1763934-ded1-11e8-a2cc-0242ac110003
https://ci.chromium.org/p/chrome/builders/luci.chrome.ci/Android%20Nexus6%20WebView%20Perf/3109
 
# Affected Tests
v8.browsing_mobile-future/browse:news:toi

# Error
Traceback (most recent call last):
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/story_runner.py", line 128, in _RunStoryAndProcessErrorIfNeeded
    test.Measure(state.platform, results)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/web_perf/timeline_based_measurement.py", line 268, in Measure
    trace_result, _ = platform.tracing_controller.StopTracing()
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/core/tracing_controller.py", line 53, in StopTracing
    return self._tracing_controller_backend.StopTracing()
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/platform/tracing_controller_backend.py", line 157, in StopTracing
    '\n'.join(raised_exception_messages))
TracingException: Exceptions raised when trying to stop tracing:
Traceback (most recent call last):
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/platform/tracing_controller_backend.py", line 145, in StopTracing
    agent.CollectAgentTraceData(builder)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent.py", line 248, in CollectAgentTraceData
    '\n'.join(raised_exception_messages))
ChromeTracingStoppedError: Exceptions raised when trying to collect Chrome devtool tracing:
Error when collecting Chrome tracing on devtools at port localabstract:webview_devtools_remote_10643:
Traceback (most recent call last):
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent.py", line 237, in CollectAgentTraceData
    client.CollectChromeTracingData(trace_data_builder)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/devtools_client_backend.py", line 489, in CollectChromeTracingData
    self._tracing_backend.CollectTraceData(trace_data_builder, timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/tracing_backend.py", line 237, in CollectTraceData
    self._CollectTracingData(trace_data_builder, timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/tracing_backend.py", line 265, in _CollectTracingData
    traceback.format_exc())
TracingUnrecoverableException: Exception raised while collecting tracing data:
Traceback (most recent call last):
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/tracing_backend.py", line 258, in _CollectTracingData
    self._inspector_websocket.DispatchNotifications(timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 156, in DispatchNotifications
    self._Receive(timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 181, in _Receive
    raise WebSocketException(err)
WebSocketException: WebSocketException of type <class 'websocket._exceptions.WebSocketConnectionClosedException'>. Error message: Connection is already closed.