All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=756875

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=4ca766e39f8072914b65756fe2d4a28239a17e338c86b3b1b203064c211ae17a


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

android-one

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970907836971563920

=== Auto-CCing suspected CL author chaopeng@chromium.org ===

Hi chaopeng@chromium.org, the bisect results pointed to your CL, please take a look at the
results.


=== BISECT JOB RESULTS ===
Perf regression found with culprit

Suspected Commit
  Author : chaopeng
  Commit : 2a88dac7dd3caf5155d4e82f08c86d12484dbf18
  Date   : Mon Aug 14 19:13:48 2017
  Subject: Reland "Overlay Scrollbar track not block hit test"

Bisect Details
  Configuration: android_one_perf_bisect
  Benchmark    : blink_perf.events
  Metric       : hit-test-lots-of-layers/hit-test-lots-of-layers
  Change       : 23.20% | 0.0509138046609 -> 0.0391037401354

Revision             Result                        N
chromium@494099      0.0509138 +- 0.000857312      6      good
chromium@494114      0.050268 +- 0.000534819       6      good
chromium@494121      0.0502613 +- 0.000411241      6      good
chromium@494123      0.0503174 +- 0.000530683      6      good
chromium@494124      0.0502988 +- 0.00053343       6      good
chromium@494125      0.0399294 +- 0.00071793       6      bad       <--
chromium@494128      0.0396346 +- 0.000210578      6      bad
chromium@494156      0.0400161 +- 0.000420156      5      bad
chromium@494212      0.0386464 +- 0.000545047      6      bad
chromium@494324      0.0391037 +- 0.000575071      6      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.events

More information on addressing performance regressions:
  http://g.co/ChromePerformanceRegressions

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970907836971563920


For feedback, file a bug with component Speed>Bisection

The CL is reverted.