Context: https://bugs.chromium.org/p/chromium/issues/detail?id=629105

This bisect: https://chromeperf.appspot.com/buildbucket_job_status/9004714727641762976

Updated the bug twice:

71 minutes ago: https://bugs.chromium.org/p/chromium/issues/detail?id=629105#c16
10 minutes ago: https://bugs.chromium.org/p/chromium/issues/detail?id=629105#c18

This has happened to me several times in the past week.