All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=844604

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=6da0ef02230a811d5261307fb38d302080fcd23d927558bbe3cb1ec4012cd9db


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

android-nexus5
chromium-rel-mac12
chromium-rel-win10

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/12e3aca4240000

📍 Found significant differences after each of 3 commits.
https://pinpoint-dot-chromeperf.appspot.com/job/12e3aca4240000

[Squad] Immutable style for LayoutMenuList inner_block. by futhark@chromium.org
https://chromium.googlesource.com/chromium/src/+/16a2164f7370d08a07206bcb2001668e56269af5

Download location: Fix an issue in getAllPrivateDownloadsDirectories. by xingliu@chromium.org
https://chromium.googlesource.com/chromium/src/+/25895d2377d9dd3181981583e49b1ccb80c8bc53

Remove base::Feature for RLS. by skobes@chromium.org
https://chromium.googlesource.com/chromium/src/+/bffdeb38782244a39bda346b180789dc6a69256b

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Looks like this could be mine.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/439e345b11104f36f63a906d141c7c7844103a50

commit 439e345b11104f36f63a906d141c7c7844103a50
Author: Rune Lillesveen <futhark@chromium.org>
Date: Tue May 22 11:24:25 2018

[Squad] Fix LayoutMenuList performance regression.

We only need to update the style of LayoutMenuList from option style
when we actually have an option_style_. If we deselect an option, we
would still not modify the ComputedStyle to remove any direction or
unicode-bidi from the previously selected option in AdjustInnerStyle.

Bug:  844612 ,  844604 
Change-Id: Ie8180b5e68d913afeb97b3a07bdba3cf310ea5d2
Reviewed-on: https://chromium-review.googlesource.com/1068867
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560534}
[modify] https://crrev.com/439e345b11104f36f63a906d141c7c7844103a50/third_party/blink/renderer/core/layout/layout_menu_list.cc