All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=776759

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=43cf2fd818fbd4d618eed8072d6d9b95aa8109a49686ccb9d75d1b7cd483d6c6


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

android-nexus5
android-webview-nexus6

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8965206310054690928

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

Hi wangxianzhu@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 : Xianzhu Wang
  Commit : 6dfcf90347222e60d56fd65231a2819d0f908c3d
  Date   : Wed Oct 18 01:41:54 2017
  Subject: Ensure update of scrollbar and caret visual rects on ancestor clip change

Bisect Details
  Configuration: android_nexus5_perf_bisect
  Benchmark    : smoothness.tough_animation_cases
  Metric       : frame_times/css_value_type_transform_complex.html?api_web_animations_N_0316
  Change       : 3.75% | 87.163107726 -> 90.4311105232

Revision             Result                   N
chromium@509546      87.1631 +- 2.57868       6      good
chromium@509611      87.0089 +- 0.818692      6      good
chromium@509644      87.0892 +- 1.49253       6      good
chromium@509646      87.424 +- 1.01342        6      good
chromium@509647      87.0503 +- 1.58405       6      good
chromium@509648      90.621 +- 1.58593        6      bad       <--
chromium@509652      90.3493 +- 0.976476      6      bad
chromium@509660      89.777 +- 1.35137        6      bad
chromium@509676      90.4311 +- 0.938418      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 --story-filter=css.value.type.transform.complex.html.api.web.animations.N.0316 smoothness.tough_animation_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8965206310054690928


For feedback, file a bug with component Speed>Bisection

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/34eef3f8a4801a129feba98afd109b8f7e7062e8

commit 34eef3f8a4801a129feba98afd109b8f7e7062e8
Author: Xianzhu Wang <wangxianzhu@chromium.org>
Date: Tue Oct 24 01:22:49 2017

Early return from PaintInvalidator::InvalidatePaint if no invalidation is needed

This is to fix the slight performance regression caused by
https://chromium-review.googlesource.com/719716 which lengthened
the code path for no invalidation.

Bug:  776759 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I85aed1c264fa05895049ea4828569929d0e1282c
Reviewed-on: https://chromium-review.googlesource.com/731575
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510987}
[modify] https://crrev.com/34eef3f8a4801a129feba98afd109b8f7e7062e8/third_party/WebKit/Source/core/paint/PaintInvalidator.cpp

Please add appropriate OSs.

Your change meets the bar and is auto-approved for M63. Please go ahead and merge the CL to branch 3239 manually. Please contact milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), gkihumba@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a66124f7993fe54228e581286f62740f75e8858b

commit a66124f7993fe54228e581286f62740f75e8858b
Author: Xianzhu Wang <wangxianzhu@chromium.org>
Date: Thu Oct 26 16:28:42 2017

Early return from PaintInvalidator::InvalidatePaint if no invalidation is needed

This is to fix the slight performance regression caused by
https://chromium-review.googlesource.com/719716 which lengthened
the code path for no invalidation.

TBR=wangxianzhu@chromium.org

(cherry picked from commit 34eef3f8a4801a129feba98afd109b8f7e7062e8)

Bug:  776759 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I85aed1c264fa05895049ea4828569929d0e1282c
Reviewed-on: https://chromium-review.googlesource.com/731575
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#510987}
Reviewed-on: https://chromium-review.googlesource.com/739756
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/branch-heads/3239@{#242}
Cr-Branched-From: adb61db19020ed8ecee5e91b1a0ea4c924ae2988-refs/heads/master@{#508578}
[modify] https://crrev.com/a66124f7993fe54228e581286f62740f75e8858b/third_party/WebKit/Source/core/paint/PaintInvalidator.cpp