All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=636361

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg1ou0vAkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgttK6ogkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgtvHGvQoM


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

android-nexus5
android-nexus7v2

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9004709901555345456

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


=== Bisection aborted ===
The bisect was aborted because The metric values for the initial "good" and "bad" revisions do not represent a clear regression.
Please contact the the team (see below) if you believe this is in error.

=== Warnings ===
The following warnings were raised by the bisect job:

 * Bisect failed to reproduce the regression with enough confidence.

===== TESTED REVISIONS =====
Revision         Mean     Std Dev   N   Good?
chromium@410444  12.9268  1.20683   12  good
chromium@410497  12.285   0.528428  8   bad

Bisect job ran on: android_nexus5_perf_bisect
Bug ID: 636361

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --also-run-disabled-tests smoothness.sync_scroll.key_mobile_sites_smooth
Test Metric: first_gesture_scroll_update_latency/http___answers.yahoo.com_question_index?qid_20110117024343AAopj8f
Relative Change: 2.04%
Score: 0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus5_perf_bisect/builds/3969
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9004709901555345456


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5833745341349888

| 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 Tests>AutoBisect.  Thank you!

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9004618087017192960

Re-kicked bisect on the Nexus 5 which looks less noisy

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9004254626095737008

Nexus 5 recovered.  Re-kicked bisect on the Nexus 7 bypassing the repro check.

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


===== SUSPECTED CL(s) =====
Subject : Style invalidation support for :first/last/only-child.
Author  : rune
Commit description:
  
Got rid of SubtreeStyleChanges for those pseudo classes. Also fixed
issue 245914 by looking at next/previous element, not node, to figure
out if we are the first. The code in checkForSiblingStyleChanges could
be restructured quite a bit and made simpler now have changedElement
(changedNode => changeElement since the input is always an element).

BUG=245914

Review-Url: https://codereview.chromium.org/2229503002
Cr-Commit-Position: refs/heads/master@{#410472}
Commit  : 798b5cdff6f50fa0d19a198f5f6e3f57425fbf05
Date    : Mon Aug 08 22:08:09 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev   N  Good?
chromium@410444  20.3214  0.404457  5  good
chromium@410471  20.6192  0.526598  5  good
chromium@410472  22.4986  0.56732   5  bad    <--
chromium@410473  22.8929  0.993538  5  bad
chromium@410475  22.7957  0.789636  5  bad
chromium@410478  22.2673  0.404319  5  bad
chromium@410484  22.4346  0.455482  5  bad
chromium@410497  22.8463  0.432231  5  bad

Bisect job ran on: android_nexus7_perf_bisect
Bug ID: 636361

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --also-run-disabled-tests smoothness.sync_scroll.key_mobile_sites_smooth
Test Metric: frame_times/http___www.reddit.com_r_programming_comments_1g96ve
Relative Change: 12.42%
Score: 99.5

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus7_perf_bisect/builds/3204
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9004254626095737008


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5841377280131072

| 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 Tests>AutoBisect.  Thank you!