All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=903162

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=a0cf34774c359b063f83f872ca3e88f6e03c70d3ed819651c3218a726d208476


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

Android Nexus6 WebView Perf

rendering.mobile - Benchmark documentation link:
  https://bit.ly/rendering-benchmarks

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/104c7555e40000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/104c7555e40000

Remove Offscreen Canvas Commit Timer histogram. by davidqu@chromium.org
https://chromium.googlesource.com/chromium/src/+/624867abc8a56c48efab78b7883f7fa913daea52
frame_times: 42.7 → 43.37 (+0.676)

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Benchmark documentation link:
  https://bit.ly/rendering-benchmarks

This regression doesn't look like a big change to me and the change that is referring to: https://crrev.com/c/1308755 only removes some (no longer useful) lines of code which wouldn't possibly increase frame_times.

No 4.6% is not something we can just sweep under the carpet like that.  Lets rebisect and see what the bots find.

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/175ef9efe40000

That said, the graph looks pretty noisy so it may be impossible to track down the culprit but it does seem there is a regression somewhere :(  We can see this metric has regressed quite a bit since ref was last updated which is troubling since this metric affects perceived smoothness. 

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/175ef9efe40000

The swarming task expired. The bots are likely overloaded, dead, or misconfigured.