Revision range first seen:

Unknown, but it's been happening since at least Build 836 (revision 0d3b9fa0d3227bc9d936c1e2dba93f53f5cff65e)

Link to failing step log:

https://build.chromium.org/p/chromium.perf/builders/Win%20Zenbook%20Perf%20%283%29/builds/999/steps/image_decoding.image_decoding_measurement.reference/logs/stdio

It appears that either tracing has stopped for some reason, or there is some kind of race condition.

Exception raised when cleaning story run: 

Traceback (most recent call last):
  _RunStoryAndProcessErrorIfNeeded at third_party\catapult\telemetry\telemetry\internal\story_runner.py:110
    test.DidRunPage(state.platform)
  DidRunPage at tools\perf\measurements\image_decoding.py:99
    platform.tracing_controller.StopTracing()
  StopTracing at third_party\catapult\telemetry\telemetry\core\tracing_controller.py:39
    return self._tracing_controller_backend.StopTracing()
  StopTracing at third_party\catapult\telemetry\telemetry\internal\platform\tracing_controller_backend.py:105
    '\n'.join(raised_exception_messages))
TracingControllerStoppedError: Exceptions raised when trying to stop tracing:
Traceback (most recent call last):
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_controller_backend.py", line 94, in StopTracing
    agent.StopAgentTracing(trace_data_builder)
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\chrome_tracing_agent.py", line 143, in StopAgentTracing
    '\n'.join(raised_execption_messages))
ChromeTracingStoppedError: Exceptions raised when trying to stop Chrome devtool tracing:
Error when trying to stop Chrome tracing on devtools at port 50472:
Traceback (most recent call last):
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\chrome_tracing_agent.py", line 128, in StopAgentTracing
    client.StopChromeTracing(trace_data_builder)
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\internal\backends\chrome_inspector\devtools_client_backend.py", line 337, in StopChromeTracing
    assert self.is_tracing_running
AssertionError

Locals:
  agent                     : <telemetry.internal.platform.tracing_controller_backend.TracingControllerBackend object at 0x0338E470>
  raised_exception_messages : ['Traceback (most recent call last):\n  File "C:\\b\\build\\slave\\Win_Zenbook_Perf__3_\\build\\src\\third_party\\catapult\\telemetry\\telemetry\\internal\\platform\\tracing_controller_backend.py", line 94, in StopTracing\n    agent.StopAgentTracing(trace_data_builder)\n  File "C:\\b\\build\\slave\\Win_Zenbook_Perf__3_\\build\\src\\third_party\\catapult\\telemetry\\telemetry\\internal\\platform\\tracing_agent\\chrome_tracing_agent.py", line 143, in StopAgentTracing\n    \'\\n\'.join(raised_execption_mess ... ile "C:\\b\\build\\slave\\Win_Zenbook_Perf__3_\\build\\src\\third_party\\catapult\\telemetry\\telemetry\\internal\\platform\\tracing_agent\\chrome_tracing_agent.py", line 128, in StopAgentTracing\n    client.StopChromeTracing(trace_data_builder)\n  File "C:\\b\\build\\slave\\Win_Zenbook_Perf__3_\\build\\src\\third_party\\catapult\\telemetry\\telemetry\\internal\\backends\\chrome_inspector\\devtools_client_backend.py", line 337, in StopChromeTracing\n    assert self.is_tracing_running\nAssertionError\n\n'] (truncated)
  trace_data_builder        : <telemetry.timeline.trace_data.TraceDataBuilder object at 0x03E76950>


Unfortunately, it also appears to timeout while trying to capture a screenshot:
(WARNING) 2016-03-03 06:29:10,298 shared_page_state._TryCaptureScreenShot:157  Exception when trying to capture screenshot: TimeoutException('',)
Traceback (most recent call last):
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\internal\story_runner.py", line 84, in _RunStoryAndProcessErrorIfNeeded
    state.RunStory(results)
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\page\shared_page_state.py", line 323, in RunStory
    self._current_page.Run(self)
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\page\__init__.py", line 84, in Run
    shared_state.page_test.RunNavigateSteps(self, current_tab)
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\page\page_test.py", line 182, in RunNavigateSteps
    page.RunNavigateSteps(action_runner)
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\tools\perf\page_sets\image_decoding_measurement.py", line 18, in RunNavigateSteps
    action_runner.WaitForJavaScriptCondition('isDone')
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\page\action_runner.py", line 186, in WaitForJavaScriptCondition
    self._tab.WaitForJavaScriptExpression(condition, timeout_in_seconds)
  File "C:\b\build\slave\Win_Zenbook_Perf__3_\build\src\third_party\catapult\telemetry\telemetry\internal\browser\web_contents.py", line 129, in WaitForJavaScriptExpression
    """))
TimeoutException: Timed out while waiting 60s for IsJavaScriptExpressionTrue.