All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=645582

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgkcr37AoM


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

linux-release

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9001970889010898240

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

Hi sunxd@chromium.org, the bisect results pointed to your CL below as possibly
causing a regression. Please have a look at this info and see whether
your CL be related.


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


===== SUSPECTED CL(s) =====
Subject : Adjust gfx::Rect's width and height to avoid integer overflow
Author  : sunxd
Commit description:
  
It is possible that the origin plus the bounds of a gfx::Rect can exceed
the range of an integer, as reflected in clusterfuzz.

This CL makes gfx::Rect adjust the width and height if origin + bounds
can result in an overflow.

BUG= 637985 
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2268423003
Cr-Commit-Position: refs/heads/master@{#416118}
Commit  : 86fc67cca4eaad94ec7bf3daebf905939abdd03c
Date    : Thu Sep 01 23:31:30 2016


===== TESTED REVISIONS =====
Revision         Mean       Std Dev      N  Good?
chromium@416105  0.03535    0.000157564  5  good
chromium@416116  0.035225   0.000151955  5  good
chromium@416117  0.0356083  0.000579302  5  good
chromium@416118  0.037475   6.97217e-05  5  bad    <--
chromium@416119  0.0374917  0.000136295  5  bad
chromium@416121  0.0374083  0.000133073  5  bad
chromium@416126  0.03755    0.000159752  5  bad

Bisect job ran on: linux_perf_bisect
Bug ID: 645582

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests rasterize_and_record_micro.top_25_smooth
Test Metric: record_time/record_time
Relative Change: 6.22%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/linux_perf_bisect/builds/6703
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9001970889010898240


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5254863850569728

| 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!

I think as we add more logic to many methods in gfx::Rect to avoid integer overflow, it is probably expected to cause the performance to slow down.

cc danakj@ for verification/discussion.

Yeh our choices are roughly: accept this regression, spend the next 6 months tracking down integer overflows, stop fixing integer overflows (ignore UBSAN essentially). It's sad but I don't have any other suggestions.

SGTM, thanks.