The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/443a130bb71122667b40bb24873274b15ecb4380

commit 443a130bb71122667b40bb24873274b15ecb4380
Author: Jordy Greenblatt <jordynass@chromium.org>
Date: Wed Jun 20 03:15:01 2018

[CrOS MultiDevice]: Fix bug in settings UI page

The basic settings page (via MainPageBehavior) searches its children
for settings-sections to hide when it expands a subpage. Because CL
https://chromium-review.googlesource.com/c/chromium/src/+/1105185
pushed the multidevice settings-section down the DOM tree, it is no
longer automatically hidden. To avoid dealing with the /deep/ selector
(see https://bugs.chromium.org/p/chromium/issues/detail?id=852098)
I just had the basic page take page expansion into account directly
when deciding whether to attach the
multidevice-settings-section-container.

Bug:  854400 
Cq-Include-Trybots: luci.chromium.try:closure_compilation
Change-Id: I89e08e5af79163146737d7ae5a9637536cb032c2
Reviewed-on: https://chromium-review.googlesource.com/1107168
Commit-Queue: Jordy Greenblatt <jordynass@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568711}
[modify] https://crrev.com/443a130bb71122667b40bb24873274b15ecb4380/chrome/browser/resources/settings/basic_page/basic_page.html
[modify] https://crrev.com/443a130bb71122667b40bb24873274b15ecb4380/chrome/browser/resources/settings/basic_page/basic_page.js

This bug has an owner, thus, it's been triaged. Changing status to "assigned".