All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=763901

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=44d1ef0c6398f08d972b89a04326738a0ecfe0ceb7f3ee247024d98021f0db1b


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

android-nexus7v2

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8968746567262197728

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

Hi chrishtr@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 : Chris Harrelson
  Commit : c3a3481c4b1b08775b477144d1d2873a2a3d9900
  Date   : Sat Sep 09 06:46:57 2017
  Subject: Implement fragmentation in the pre-paint tree walk.

Bisect Details
  Configuration: android_nexus7_perf_bisect
  Benchmark    : smoothness.tough_animation_cases
  Metric       : frame_times/mix_blend_mode_propagating_isolation.html
  Change       : 9.14% | 18.2495887814 -> 19.9168476653

Revision             Result                   N
chromium@500791      18.2496 +- 0.247009      6      good
chromium@500792      19.8285 +- 0.490148      6      bad       <--
chromium@500793      19.9316 +- 0.455033      6      bad
chromium@500794      19.9168 +- 0.405697      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=mix.blend.mode.propagating.isolation.html 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/8968746567262197728


For feedback, file a bug with component Speed>Bisection

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7aad31c7261baf6b9cc88bd6cdbeb772db0efc9c

commit 7aad31c7261baf6b9cc88bd6cdbeb772db0efc9c
Author: Chris Harrelson <chrishtr@chromium.org>
Date: Tue Sep 12 06:21:47 2017

Micro-optimize common code in PaintPropertyTreeBuilder.

1. Avoid multiple adjacent calls to MutableForPainting().
2. Avoid computing the containing composited layer unless
fragmentation is present.

Bug:  763901 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Icea7cdd99c23860f6d853a3dbfcb51f10e8dd24d
Reviewed-on: https://chromium-review.googlesource.com/660681
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Tien-Ren Chen <trchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501202}
[modify] https://crrev.com/7aad31c7261baf6b9cc88bd6cdbeb772db0efc9c/third_party/WebKit/Source/core/paint/PaintLayer.cpp
[modify] https://crrev.com/7aad31c7261baf6b9cc88bd6cdbeb772db0efc9c/third_party/WebKit/Source/core/paint/PaintLayer.h
[modify] https://crrev.com/7aad31c7261baf6b9cc88bd6cdbeb772db0efc9c/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
[modify] https://crrev.com/7aad31c7261baf6b9cc88bd6cdbeb772db0efc9c/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h

Micro-optimizations worked! Performance is back to normal.