Version: 54.0.2823.0 Dev
OS: Ubuntu 14.04, Windows

Pre-condition: Make sure to have more history such that vertical scrollbar appears.

What steps will reproduce the problem?
(1)Launch chrome>>Navigate to Chrome://history>>Open devtools and emulate
(2)Now click on reload or hit Ctrl+r>>Toggle back from emulation and observe vertical scrollbar 

Expected:Vertical scrollbar should be seen after reloading chrome://history page in emulation view and toggling back.
Actual:Instead vertical scrollbar is seen missing.

This is Regression issue broken in M-50.
Good build:50.0.2645.0 Dev
Bad build:50.0.2646.0 Dev

CHANGELOG URL:  https://chromium.googlesource.com/chromium/src/+log/02b81ba466ca5698cdd8bcee2ae2aa4401589b7d..6b19aeb11c4349ff517e00f379545943e7d2d980

Unable to find suspect from narrow bisect. Hence providing manual changelog.

Manual changelog:
https://chromium.googlesource.com/chromium/src/+log/50.0.2645.0..50.0.2646.0?pretty=fuller&n=10000

Suspecting https://codereview.chromium.org/1673393002 from manual change log.

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

Attaching screen-cast for reference.
 

Deleted: Expected.ogv 3.0 MB

	Expected.ogv 3.0 MB View Download

Deleted: Actual.ogv 3.1 MB

	Actual.ogv 3.1 MB View Download