All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=674522

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgj7W1oQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgj8z0tgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg99bRoQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgj4r9uQkM


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

chromium-rel-win7-gpu-ati
chromium-rel-win7-gpu-nvidia
linux-release

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8993203368077494464

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


===== SUSPECTED CL(s) =====
Subject : SELECT element: Fix a bug that intrinsic width is too narrow in less-than-100% zoom level.
Author  : tkent
Commit description:
  
This is a regression by  crbug.com/432795 .  Scrollbar thickness is fixed regardless
of zoom level.  So popup width was too narrow in less-than-100% zoom level.

With this CL, popupInternalPaddingEnd() returns zoomed value as ever if zoom level
is 100%+, and returns a value based on actual scrollbar thickness otherwise.

Also, popupIntenalPaddingEnd() respects to the actual scrollbar thickness instead
of returning fixed '18' pixel.  The default scrollbar thickness on Windows is 17.
popupInternalPaddingEnd() returns 1 + <scrollbar thickness>.

We need to update ThemePainterDefault::setupMenuListArrow() so that it can support
variable width of scrollbars.

Summary of behavior changes:

All platforms except Mac:
  menulist box is wider in less-than-100% zoom level.

Windows Aura theme:
  menulist box is not changed in 100%+ zoom level.

Non-Windows Aura theme and Mock theme:
  menulist box  is narrower by 2px because scrollbar thickness is 15px.

BUG= 667236 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2560733002
Cr-Commit-Position: refs/heads/master@{#437864}
Commit  : 0151427d8ecd6ff854cffb3b741673ab043f7bd0
Date    : Mon Dec 12 14:10:20 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N   Good?
chromium@437841  325.247  20.7018  30  good
chromium@437853  322.425  10.1833  30  good
chromium@437859  325.173  12.1244  30  good
chromium@437862  325.441  27.1167  30  good
chromium@437863  327.796  25.3974  30  good
chromium@437864  290.691  10.6327  30  bad    <--
chromium@437865  297.455  16.2277  30  bad

Bisect job ran on: winx64nvidia_perf_bisect
Bug ID: 674522

Test Command: src/tools/perf/run_benchmark -v --browser=release_x64 --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.dom
Test Metric: select-single-remove/select-single-remove
Relative Change: 8.54%

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/winx64nvidia_perf_bisect/builds/1978
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8993203368077494464


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5795414287056896

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