Version:54.0.2806.0 Dev
OS: Ubuntu 14.04,Windows

Pre condition:Make sure you have more history.

What steps will reproduce the problem?
(1)Sign-in to chrome with valid credentials>>Navigate to chrome://history >>Resize the window such that Horizontal scrollbar is seen.
(2)Open devtools and emulate>>Resize devtools window to R.H.S such that Responsive drop-down appears and select Nexus5X from drop-down
(3)Now Off emulation and observe for horizontal scrollbar.

Expected:Horizontal scrollbar should be seen after toggling back from emulation view.
Actual:Instead horizontal scrollbar is seen missing.

This is a Regression issue broken in M54. Unable to do tool bisect as issue is seen only after signing into chrome which can't be done in chromium builds.

Manual Bisect info:
Good Build:54.0.2788.0 Dev
Bad Build:54.0.2789.0 Dev

Changelog:
https://chromium.googlesource.com/chromium/src/+log/54.0.2788.0..54.0.2789.0?pretty=fuller&n=10000

Suspecting https://codereview.chromium.org/2084843002 from manual change log.

@calamity: Please help in re-assigning if it is not related to your change.

Attaching screen-cast for reference.
 

Deleted: Expected_Scrollbar.ogv 2.8 MB

	Expected_Scrollbar.ogv 2.8 MB View Download

Deleted: Actual_Scrollbar.ogv 6.2 MB

	Actual_Scrollbar.ogv 6.2 MB View Download