All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=766885

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=12ec4d4e125bd2bdb0b963d106b5b57a330520d2be611d18e82a5d5c3b3db0e9


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

chromium-rel-win10
chromium-rel-win7-dual
chromium-rel-win7-gpu-ati

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8967980083351608352

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

Suspected Commit
  Author : Bruce Dawson
  Commit : eaccacb6302f7b0ea235fd7d1ff3aa7eaf8b20ef
  Date   : Mon Sep 18 06:35:37 2017
  Subject: Revert "Make VS 2017 the default compiler on Windows"

Bisect Details
  Configuration: winx64_10_perf_bisect
  Benchmark    : media_perftests
  Metric       : clockless_video_playback_vp9/bear-vp9.webm
  Change       : 1.79% | 27.2239476187 -> 26.736727857

Revision             Result                   N
chromium@502529      27.2239 +- 0.145935      6      good
chromium@502533      27.2393 +- 0.105894      6      good
chromium@502534      27.1912 +- 0.123914      6      good
chromium@502535      26.7267 +- 0.092208      6      bad       <--
chromium@502537      26.7367 +- 0.101822      6      bad

To Run This Test
  .\src\out\Release_x64\media_perftests.exe --single-process-tests

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8967980083351608352


For feedback, file a bug with component Speed>Bisection