Chrome Version: 69.0.3497.23 (Official Build) Revision	a0f931c424245a817bf2ad63eb45c6c95f28e1ee-refs/branch-heads/3497@{#301}(64 bit)
OS: Windows(7,8,8.1,10)

Pre-condition: Enable 'Enable using Google Local NTP' and 'New Tab Page Background Selection' under 'chrome://flags'.

What steps will reproduce the problem?
(1) Launch Chrome, open NTP and click on Gear icon in bottom RHS of page.
(2) Click on 'Chrome Backgrounds' and observe the 'Select a collection' overlay.

Actual Result  :Unwanted blank space is seen on right side of the 'Select a collection' overlay.
Expected Result:Unwanted blank space should not be seen on right side of the 'Select a collection' overlay.

This is regression issue broken in ‘M-69’ and below is the bisect info:

Good build: 69.0.3494.0(Revision: 575514)
Bad build : 69.0.3495.0(Revision: 575926)

You are probably looking for a change made after 575755 (known good), but no later than 575759 (first known bad).

Narrow Bisect info :

https://chromium.googlesource.com/chromium/src/+log/f1717d24eb02cbe374d01ef29dff42199bd636de..f48f31cd85dd7444fd9b58e407b72f0191b48109

Suspect: r575756 ?

@kmilka: Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Kindly review the attached screen-cast for reference.

Note: 
1)Issue is not reproducible on Mac(10.12.6,10.13.1,10.13.6) OS.
2)Gear icon is not present in Linux (14.04 LTS) OS.

Thank You!
 

Deleted: Actual_Result.mp4 763 KB

	Actual_Result.mp4 763 KB View Download

Deleted: Expected_Result.mp4 930 KB

	Expected_Result.mp4 930 KB View Download