This might be a similar issue as issue crbug.com/891878.  


Link to most recently failing build: 
https://ci.chromium.org/p/chrome/builders/luci.chrome.ci/Android%20Nexus5X%20WebView%20Perf/3062

Link to logs:
https://chrome-isolated.appspot.com/browse?namespace=default-gzip&digest=1e33e9e5775b89f6fe87de027472340d245a67d7&as=benchmark_log.txt 

Snippet
(INFO) 2018-10-08 10:08:36,214 cache_temperature.EnsurePageCacheTemperature:179  PageCacheTemperature: any
(WARNING) 2018-10-08 10:08:36,522 inspector_log._OnMessage:26  DevTools console [network]: Failed to load resource: the server responded with a status of 404 (File not found) http://127.0.0.1:38031/favicon.ico
(INFO) 2018-10-08 10:08:43,281 cmd_helper._ValidateAndLogCommand:160  [host]> /b/swarming/w/ir/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb -s 02020871c2a35531 shell '( uiautomator dump /data/local/tmp/temp_file-2f511c0ce24aa );echo %$?'
(INFO) 2018-10-08 10:08:45,879 cmd_helper._ValidateAndLogCommand:160  [host]> /b/swarming/w/ir/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb -s 02020871c2a35531 pull /data/local/tmp/temp_file-2f511c0ce24aa /b/swarming/w/itbCL6QC/tmpPpEIgz/tmp_ReadFileWithPull
(INFO) 2018-10-08 10:08:46,045 cmd_helper._ValidateAndLogCommand:160  [host]> /b/swarming/w/ir/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb -s 02020871c2a35531 shell 'rm -f /data/local/tmp/temp_file-2f511c0ce24aa'
(INFO) 2018-10-08 10:08:46,048 cmd_helper._ValidateAndLogCommand:160  [host]> /b/swarming/w/ir/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb -s 02020871c2a35531 shell '( ( logcat -d -t 500 )>/data/local/tmp/temp_file-d916dd9d29463 2>&1 );echo %$?'
(INFO) 2018-10-08 10:08:46,155 cmd_helper._ValidateAndLogCommand:160  [host]> /b/swarming/w/ir/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb -s 02020871c2a35531 pull /data/local/tmp/temp_file-d916dd9d29463 /b/swarming/w/itbCL6QC/tmpDQ15L7/tmp_ReadFileWithPull
(INFO) 2018-10-08 10:08:46,323 cmd_helper._ValidateAndLogCommand:160  [host]> /b/swarming/w/ir/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb -s 02020871c2a35531 shell 'rm -f /data/local/tmp/temp_file-d916dd9d29463'
(ERROR) 2018-10-08 10:08:46,726 story_runner.ProcessError:100  Handleable error
Traceback (most recent call last):
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/story_runner.py", line 126, in _RunStoryAndProcessErrorIfNeeded
    state.RunStory(results)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/page/shared_page_state.py", line 300, in RunStory
    self._current_page.Run(self)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/page/__init__.py", line 99, in Run
    self.RunPageInteractions(action_runner)
  File "/b/swarming/w/ir/tools/perf/benchmarks/blink_perf.py", line 40, in RunPageInteractions
    action_runner.WaitForJavaScriptCondition('testRunner.isDone', timeout=600)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/actions/action_runner.py", line 261, in WaitForJavaScriptCondition
    return self._tab.WaitForJavaScriptCondition(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/browser/web_contents.py", line 239, in WaitForJavaScriptCondition
    return self._inspector_backend.WaitForJavaScriptCondition(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 290, in WaitForJavaScriptCondition
    return py_utils.WaitFor(IsJavaScriptExpressionTrue, timeout)
  File "/b/swarming/w/ir/third_party/catapult/common/py_utils/py_utils/__init__.py", line 136, in WaitFor
    res = condition()
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 287, in IsJavaScriptExpressionTrue
    return self._EvaluateJavaScript(condition, context_id, timeout)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 41, in Inner
    inspector_backend._ConvertExceptionFromInspectorWebsocket(e)
  File "/b/swarming/w/ir/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
    return func(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 38, in Inner
    return func(inspector_backend, *args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py", line 540, in _EvaluateJavaScript
    self._runtime.Crash(context_id, timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_runtime.py", line 81, in Crash
    res = self._inspector_websocket.SyncRequest(request, timeout)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 129, in SyncRequest
    self._SendRequest(req)
  File "/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_websocket.py", line 119, in _SendRequest
    raise WebSocketException(err)
TimeoutException: 
********************************************************************************
(/b/swarming/w/ir/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py:503 _ConvertExceptionFromInspectorWebsocket) The app is probably crashed: