All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=592289

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDAv8K27ggM


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

chromium-rel-mac10

===== 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 Value  Std. Dev.   Num Values  Good?
chromium@378705         3011.880645 41.800972   62          good
chromium@378709         3020.983871 42.021919   62          bad

Bisect job ran on: mac_10_10_perf_bisect
Bug ID: 592289

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --also-run-disabled-tests startup.cold.blank_page
Test Metric: first_main_frame_load_time/first_main_frame_load_time
Relative Change: 0.69%
Score: 0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_10_perf_bisect/builds/2024
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9018879457708592768


| 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 label Cr-Tests-AutoBisect.  Thank you!

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

Hi msw@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 : Simplify ash shelf layout code.
Author  : msw
Commit description:
  
Remove Shelf::[G|S]etShelfViewBounds.
Remove ShelfWidget::DelegateView::Layout override.
Use FillLayout instead, with an empty border on the parent.

Use ScreenUtil::GetShelfDisplayBoundsInRoot consistently.
Refactor ShelfLayoutManager::CalculateTargetBounds, etc.

BUG= 57406 
TEST=No behavior changes or regressions.
R=sky@chromium.org

Review URL: https://codereview.chromium.org/1742953002

Cr-Commit-Position: refs/heads/master@{#378707}
Commit  : 932c2ee1d4a454f926a725c38a3b5f78c88a0667
Date    : Wed Mar 02 07:00:42 2016


===== TESTED REVISIONS =====
Revision                Mean Value  Std. Dev.   Num Values  Good?
chromium@378705         3048.4      29.312533   27          good
chromium@378706         3058.6      28.27821    8           good
chromium@378707         3125.32     52.412327   5           bad
chromium@378709         3069.944444 28.106755   18          bad

Bisect job ran on: mac_10_10_perf_bisect
Bug ID: 592289

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --also-run-disabled-tests startup.cold.blank_page
Test Metric: first_main_frame_load_time/first_main_frame_load_time
Relative Change: 0.89%
Score: 95.0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_10_perf_bisect/builds/2025
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9018879449990219152


| 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 label Cr-Tests-AutoBisect.  Thank you!

My CL only affects Chrome OS, it wouldn't cause a regression on chromium-rel-mac10 or mac_10_10_perf_bisect.
Eric, can you help find the actual cause? The CL range doesn't have any clear suspects:
https://chromium.googlesource.com/chromium/src/+log/076d08769a8e110e841ae5f9ca949a9f3749be30%5E..66d7184c7db7a657022286412716a0ac1912896b?pretty=fuller

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


===== SUSPECTED CL(s) =====
Subject : Reland: Bootstrap Mojo IPC independent of Chrome IPC
Author  : rockot
Commit description:
  
The original CL:
https://crrev.com/eb199fbaecd8e5d294010dfbe8897b7d83aeab07

broke NaCL integration tests on some bots. After some
extensive investigation this is somehow tied to an
obscure dependency on the value of kIPCDescriptorMax.
Moving kMojoIPCChannel to content_descriptors.h allows
us to avoid changing that value and thus avoid the
mysterious breakage. :|

Original CL description follows:

This initializes Mojo IPC very early in child process
startup so we can start using cross-process pipes in
content without a dependency on Chrome IPC.

On all supported platforms, a new OS pipe handle is
passed through ChildProcessLauncher and hooked up to
the EDK on ChildThreadImpl startup to establish a
Mojo IPC channel to the parent.

A command-line argument is also to used to share a
unique pipe token with the child, and this token is
exchanged over the Mojo IPC channel to bootstrap a
primordial message pipe.

While this CL establishes these facilities in a way
that can be used for all child processes, only
render processes are brought up in this way for now.

BUG= 583557 
TEST=Chrome still runs in mash with Mus-in-renderer support.
TBR=ben@chromium.org,jschuh@chromium.org

Review URL: https://codereview.chromium.org/1747053003

Cr-Commit-Position: refs/heads/master@{#378704}
Commit  : e8b8da4b8f513b7ab03bb2e2eb9156bc828267a5
Date    : Wed Mar 02 06:21:38 2016


===== TESTED REVISIONS =====
Revision                Mean Value  Std. Dev.   Num Values  Good?
chromium@378605         2802.88     98.991777   5           good
chromium@378671         2829.2      23.94619    5           good
chromium@378689         2842.68     37.135859   5           good
chromium@378698         2845.4      15.45639    5           good
chromium@378701         2840.72     27.861299   5           good
chromium@378703         2827.04     45.868813   5           good
chromium@378704         3043.88     12.575055   5           bad
chromium@378737         3022.52     34.476833   5           bad

Bisect job ran on: mac_10_10_perf_bisect
Bug ID: 592289

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --also-run-disabled-tests startup.cold.blank_page
Test Metric: first_main_frame_load_time/first_main_frame_load_time
Relative Change: 7.84%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_10_perf_bisect/builds/2030
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9018707791050394608


| 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 label Cr-Tests-AutoBisect.  Thank you!