webrtc.datachannel failing on 2 builders

Builders failed on: 
- Android Nexus5X Perf (2): 
  https://build.chromium.org/p/chromium.perf/builders/Android%20Nexus5X%20Perf%20%282%29
- Android Nexus6 Perf (2): 
  https://build.chromium.org/p/chromium.perf/builders/Android%20Nexus6%20Perf%20%282%29


Failure Output:
https://luci-logdog.appspot.com/v/?s=chrome%2Fbb%2Fchromium.perf%2FAndroid_Nexus6_Perf__2_%2F5140%2F%2B%2Frecipes%2Fsteps%2Fwebrtc.datachannel%2F0%2Fstdout

Snippet:
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Traceback (most recent call last):
  File "/b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/story_runner.py", line 88, in _RunStoryAndProcessErrorIfNeeded
    state.RunStory(results)
  File "/b/c/b/Android_Nexus6_Perf__2_/src/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/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/page/shared_page_state.py", line 301, in RunStory
    self._current_page, self._current_tab, results)
  File "/b/c/b/Android_Nexus6_Perf__2_/src/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/c/b/Android_Nexus6_Perf__2_/src/tools/perf/measurements/webrtc.py", line 61, in ValidateAndMeasurePage
    self._power_metric.Stop(page, tab)
  File "/b/c/b/Android_Nexus6_Perf__2_/src/tools/perf/metrics/power.py", line 100, in Stop
    self._StopInternal()
  File "/b/c/b/Android_Nexus6_Perf__2_/src/tools/perf/metrics/power.py", line 52, in _StopInternal
    self._results = self._platform.StopMonitoringPower()
  File "/b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/core/platform.py", line 311, in StopMonitoringPower
    ret_val = self._platform_backend.StopMonitoringPower()
  File "/b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/platform/android_platform_backend.py", line 433, in StopMonitoringPower
    return self._power_monitor.StopMonitoringPower()
  File "/b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/platform/power_monitor/android_power_monitor_controller.py", line 79, in StopMonitoringPower
    self._MergePowerResults(results, monitor.StopMonitoringPower())
  File "/b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py", line 76, in StopMonitoringPower
    self._platform.ParseCStateSample(self._initial_cstate),
  File "/b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/platform/android_platform_backend.py", line 497, in ParseCStateSample
    cstates[state] = int(times[i])
ValueError: invalid literal for int() with base 10: ''

INFO:root:Closing power monitors
INFO:root:IsMonitoringPower: True
INFO:root:Try printing formatted exception: None None None

Exception raised when cleaning story run: 

Traceback (most recent call last):
  _RunStoryAndProcessErrorIfNeeded at /b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/story_runner.py:113
    test.DidRunPage(state.platform)
  traced_function at /b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
    return func(*args, **kwargs)
  DidRunPage at /b/c/b/Android_Nexus6_Perf__2_/src/tools/perf/measurements/webrtc.py:69
    self._power_metric.Close()
  Close at /b/c/b/Android_Nexus6_Perf__2_/src/tools/perf/metrics/power.py:106
    self._platform.StopMonitoringPower()
  StopMonitoringPower at /b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/core/platform.py:311
    ret_val = self._platform_backend.StopMonitoringPower()
  StopMonitoringPower at /b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/platform/android_platform_backend.py:433
    return self._power_monitor.StopMonitoringPower()
  StopMonitoringPower at /b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/platform/power_monitor/android_power_monitor_controller.py:74
    self._CheckStop()
  _CheckStop at /b/c/b/Android_Nexus6_Perf__2_/src/third_party/catapult/telemetry/telemetry/internal/platform/power_monitor/__init__.py:35
    assert self._monitoring, "Not monitoring power."
AssertionError: Not monitoring power.

Locals:
  No locals!

[  FAILED  ] 30s_datachannel_transfer (50059 ms)
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