All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=734623

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9vn56QsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtsaopQgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1pWAyQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtt3g-QgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9rK2pAkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9pLp4wgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9sPUtQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtu3MogoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtsaoxQgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9sG9vAkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9szDsAoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtpyP_gsM


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

chromium-rel-mac12

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8976339608883201648

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

Hi adamk@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 : Adam Klein
  Commit : 8196e102654935eb780c8fa868b97d3409b7c0e6
  Date   : Tue Jun 13 19:12:15 2017
  Subject: [builtins] Move most WeakMap/WeakSet code from JS to C++ builtins

Bisect Details
  Configuration: mac_10_12_perf_bisect
  Benchmark    : media.tough_video_cases_tbmv2
  Metric       : memory:chrome:renderer_processes:reported_by_chrome:v8:heap:code_space:effective_size_avg/video.html?src_garden2_10s.mp4_seek
  Change       : 0.20% | 1260512.0 -> 1263077.33333

Revision                           Result                  N
chromium@479335                    1260512 +- 0.0          6      good
chromium@479365                    1261504 +- 0.0          6      good
chromium@479380                    1261541 +- 204.483      6      good
chromium@479384                    1261541 +- 204.483      6      good
chromium@479385                    1261504 +- 0.0          6      good
chromium@479385,v8@041d7339e3      1261504 +- 0.0          6      good
chromium@479385,v8@8196e10265      1262624 +- 0.0          6      bad       <--
chromium@479385,v8@b11c557d32      1263040 +- 0.0          6      bad
chromium@479385,v8@aea68b5a26      1263077 +- 204.483      6      bad
chromium@479385,v8@7e6ed62071      1263077 +- 204.483      6      bad
chromium@479386                    1263077 +- 204.483      6      bad
chromium@479388                    1263077 +- 204.483      6      bad
chromium@479395                    1263077 +- 204.483      6      bad

To Run This Test
  src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=video.html.src.garden2.10s.mp4.seek media.tough_video_cases_tbmv2

Debug Info
  https://chromeperf.appspot.com/buildbucket_job_status/8976339608883201648

Is this bisect wrong?
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5258018129707008


| 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!

Already reverted.