All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=699719

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgxNaq8QkM


Bot(s) for this bug's original alert(s):

android-nexus5X

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8985654676586475584

=== BISECT JOB RESULTS ===
NO Perf regression found

Bisect Details
  Configuration: android_nexus5X_perf_bisect
  Benchmark    : blink_perf.bindings
  Metric       : structured-clone-json-serialize/structured-clone-json-serialize

Revision             Result                  N
chromium@451843      45.164 +- 49.7095       21      good
chromium@452846      47.5203 +- 51.7612      21      bad

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.bindings

Debug Info
  https://chromeperf.appspot.com/buildbucket_job_status/8985654676586475584

Is this bisect wrong?
  https://chromeperf.appspot.com/bad_bisect?try_job_id=6157081012338688


| O O | Visit http://www.chromium.org/developers/speed-infra/perf-bug-faq
|  X  | for more information addressing perf regression bugs. For feedback,
| / \ | file a bug with component Speed>Bisection.  Thank you!

Not sure how much time to spend on this.

jbroman@, do you know any recent change about structured clone?
Could you take a look?

I think this bug is a false alarm. If you click the tooltips before/after the alert, you get to the buildbot status pages:
https://build.chromium.org/p/chromium.perf/builders/Android%20Nexus5X%20Perf%20%283%29/builds/3457
https://build.chromium.org/p/chromium.perf/builders/Android%20Nexus5X%20Perf%20%283%29/builds/3458

Looking at device_status step it looks like the devices were completely swapped out. There is no reference build, and this doesn't happen on any other device type, and bisect can't reproduce. I'm going to WontFix since I believe it happened due to the device swap, but please reopen if anyone disagrees.

That makes sense and good to know of device_status section.