The tests have been failing on Win 10 High-DPI Perf (4) for a few weeks:
https://uberchromegw.corp.google.com/i/chromium.perf/builders/Win%2010%20High-DPI%20Perf%20%284%29?numbuilds=200

They are also very flaky on Win Zenbook Perf (4):
https://uberchromegw.corp.google.com/i/chromium.perf/builders/Win%20Zenbook%20Perf%20%284%29?numbuilds=200




C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\image_processing\_bitmap.py:152: UserWarning: Using pure python png decoder, which could be very slow. To speed up, consider installing numpy & cv2 (OpenCV).
  'Using pure python png decoder, which could be very slow. To speed up, '
Traceback (most recent call last):
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\story_runner.py", line 86, in _RunStoryAndProcessErrorIfNeeded
    state.RunStory(results)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\common\py_trace_event\py_trace_event\trace_event_impl\decorators.py", line 75, in traced_function
    return func(*args, **kwargs)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\page\shared_page_state.py", line 310, in RunStory
    self._current_page.Run(self)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\page\__init__.py", line 109, in Run
    self.RunPageInteractions(action_runner)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\tools\perf\page_sets\system_health\system_health_story.py", line 112, in RunPageInteractions
    self._DidLoadDocument(action_runner)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\tools\perf\page_sets\system_health\browsing_stories.py", line 70, in _DidLoadDocument
    self._ReadNewsItem(action_runner)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\tools\perf\page_sets\system_health\browsing_stories.py", line 75, in _ReadNewsItem
    action_runner.tab.WaitForDocumentReadyStateToBeComplete()
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\browser\web_contents.py", line 70, in WaitForDocumentReadyStateToBeComplete
    'document.readyState == "complete"', timeout)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\browser\web_contents.py", line 136, in WaitForJavaScriptExpression
    e.message + '\n' + debug_message)
TimeoutException: Timed out while waiting 90s for IsJavaScriptExpressionTrue.
Console output:


INFO:root:Chrome version: 2885
ERROR:root:Error when deleting c:\users\chrome~1.lab\appdata\local\temp\tmpckqbtd, will try again at exit.
Traceback (most recent call last):
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_controller_backend.py", line 275, in CollectAgentTraceData
    os.remove(self._trace_log)
WindowsError: [Error 32] The process cannot access the file because it is being used by another process: 'c:\\users\\chrome~1.lab\\appdata\\local\\temp\\tmpckqbtd'
INFO:root:Try printing formatted exception: None None None

Exception raised when cleaning story run: 

Traceback (most recent call last):
  _RunStoryAndProcessErrorIfNeeded at C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\story_runner.py:108
    test.DidRunStory(state.platform)
  DidRunStory at C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\web_perf\timeline_based_measurement.py:309
    platform.tracing_controller.StopTracing()
  StopTracing at C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\core\tracing_controller.py:47
    return self._tracing_controller_backend.StopTracing()
  StopTracing at C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_controller_backend.py:133
    '\n'.join(raised_exception_messages))
TracingControllerStoppedError: Exceptions raised when trying to stop tracing:
Traceback (most recent call last):
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_controller_backend.py", line 121, in StopTracing
    agent.CollectAgentTraceData(builder)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\chrome_tracing_agent.py", line 247, 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 58127:
Traceback (most recent call last):
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\chrome_tracing_agent.py", line 236, in CollectAgentTraceData
    client.CollectChromeTracingData(trace_data_builder)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\devtools_client_backend.py", line 369, in CollectChromeTracingData
    self._tracing_backend.CollectTraceData(trace_data_builder, timeout)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\tracing_backend.py", line 227, in CollectTraceData
    self._CollectTracingData(trace_data_builder, timeout)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\tracing_backend.py", line 248, in _CollectTracingData
    self._inspector_websocket.DispatchNotifications(timeout)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\inspector_websocket.py", line 134, in DispatchNotifications
    self._Receive(timeout)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\inspector_websocket.py", line 168, in _Receive
    self._HandleAsyncResponse(result)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\inspector_websocket.py", line 184, in _HandleAsyncResponse
    callback(result)
  File "C:\b\c\b\Win_10_High_DPI_Perf__4_\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\tracing_backend.py", line 80, in _GotChunkFromStream
    trace_string = ''.join(self._data)
MemoryError