Chrome Version: 53.0.2760.0 851eb42016eeca7ac932921164bb1fdb3a5844b3-refs/heads/master@{#397956} (32/64-bit)
OS: Windows(7,8,8.1,10), Linux (14.04 LTS), Mac OS X(10.10.5, 10.11.4)

URL: https://chrome.google.com/webstore/detail/wolf-and-the-ice-planet/gffkhmkbijdmbncaoclaclldnbndflck?hl=en

Steps:
(1)Launch chrome,navigate to above url and click on 'ADD TO CHROME'
(2)Open NTP, press 'ctrl+' key and  observe.

Actual:Unwanted white patch is observed after pressing 'ctrl+' key.

Expected:No unwanted white patch should be seen after pressing 'ctrl+' key.

This is a regression This is a regression issue,broken in 'M-50'

Good Build:50.0.2633.3
Bad Build:50.0.2634.0

Narrow Bisect:
https://chromium.googlesource.com/chromium/src/+log/120a7c8d5e882458dbebd6b302087ccb2cc8ed6f..587840943312698e8de4714d21673788c4eaf16b?pretty=fuller&n=100

Suspecting:r372163?

Kindly help to re-assign if your change is not the cause for this issue.
 

Deleted: Actual theme.mp4 1.2 MB

Actual theme.mp4 1.2 MB Download

Deleted: Expected theme.mp4 753 KB

Expected theme.mp4 753 KB Download