Here's the most interesting things I'm seeing in the log:

ValueError: invalid literal for long() with base 10: 'SurfaceFlinger appears to be unresponsive (Connection timed out [-110]), dumping anyways (no locks held)'

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(/b/build/slave/Android_Nexus5X_WebView_Perf__2_/build/src/third_party/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_backend.py:315 _ConvertExceptionFromInspectorWebsocket) The app is probably crashed:

Found Minidump: True
Stack Trace:
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Return code bisect job here: https://chromeperf.appspot.com/buildbucket_job_status/9007676872260428416

This bot remains mostly red.

However, it has run several times with smoothness.top_25_smooth passing (e.g. build #670 here:  https://uberchromegw.corp.google.com/i/chromium.perf/builders/Android%20Nexus5X%20WebView%20Perf%20%282%29/builds/670/steps/smoothness.top_25_smooth)

It looks to me like the hardware/infra-structure is flaky here, causing different tests to fail at different times. Occasionally (i.e. #637) it struggles all the way to green.

I'm adding infra-troopers label as swapping out the machine or performing a cold reset might fix this chronic flakiness?

This builder is largely successful now. Can we close?