All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=631434

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg2pPPuwkM


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

chromium-rel-mac-retina

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9006079026364776736

===== BISECT JOB RESULTS =====
Status: completed


===== SUSPECTED CL(s) =====
Subject : Fix infinite recursion crash in HarfBuzz' CoreText backend
Author  : drott
Commit description:
  
The font cascade reconfiguration which was introduced as fix for AAT
shaping performance regressions in  crbug.com/547912  seems to
occasionally cause CoreText crashes on OS X 10.9. We don't have a better
way of detecting this than by OS or CoreText API version number. This is
one of our top Mac crashers on Mac OS 10.9 with Chrome across versions [1].

This crash does not occur in newer versions of OS X and we can keep this
important performance optimization enabled there.

A big thanks to Robert Sesek (rsesek@) for the patient and thorough
initial investigation. Discussing and working together on this issue we
were able to identify the crash triggering code in HarfBuzz in this
case.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=576941#c74

BUG= 576941 ,  625902 

Review-Url: https://codereview.chromium.org/2173883002
Cr-Commit-Position: refs/heads/master@{#407185}
Commit  : 64a2d4d02ea769c849df4718d196df12a3f79091
Date    : Fri Jul 22 17:18:48 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N  Good?
chromium@407175  843.338  19.5786  5  good
chromium@407183  851.03   6.92059  5  good
chromium@407184  850.382  4.57826  5  good
chromium@407185  5062.7   13.575   5  bad    <--
chromium@407187  5064.52  13.2643  5  bad
chromium@407191  5065.77  10.405   5  bad
chromium@407206  5059.06  9.94843  5  bad

Bisect job ran on: mac_retina_perf_bisect
Bug ID: 631434

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests page_cycler.intl_ko_th_vi
Test Metric: cold_times/page_load_time
Relative Change: 499.89%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_retina_perf_bisect/builds/1445
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9006079026364776736


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5780628415447040

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