Chrome Version:70.0.3521.0 (Official Build) Revision	96b3e88306e2a71a9e1f4c77a79e39f597c199b9-refs/branch-heads/3521@{#1}(64-bit)
OS:Mac(10.12.6, 10.13.1, 10.13.6), Windows(7,8,8.1,10)and Linux(14.04 LTS).

Pre-condition:
Enable following flags from chrome://flags/
-Force UI direction
-Enable using the Google local NTP
-New Tab Page Background Selection

Steps to reproduce:
1.Launch chrome and open NTP.
2.Set background in chrome from chrome background option by clicking on gear icon present on page.
3.Hover Mouse on ('x')  present on thumbnails.
4.Observe ('x').

Actual Result:Top left corner of thumbnails turns white while hovering mouse on ('x').
Expected Result:No such white effect should be seen while hovering mouse on ('x').

This is a regression issue, broken in 'M-69', and below is per-revision bisect-info:
Good Build:69.0.3493.0(Revision:575195)
Bad Build: 69.0.3494.0(Revision:575513)

You are probably looking for a change made after 575281 (known good), but no later than 575282 (first known bad).
CHANGE-LOG URL:
The script might not always return single CL as suspect as some perf builds might get missing due to failure.
  https://chromium.googlesource.com/chromium/src/+log/e0ca7658cdbb708cd2751cc1e62ffae6ac04d313..1e4aad1144bfd4bfce15120e0c79a9483e90fd46

Suspect:https://chromium.googlesource.com/chromium/src/+/1e4aad1144bfd4bfce15120e0c79a9483e90fd46

@kristipark : 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 refer the attached screen-cast 
Thank You.
 
 

Deleted: Actual_Result.mp4 1.0 MB

	Actual_Result.mp4 1.0 MB View Download

Deleted: Expected_Result.mp4 657 KB

	Expected_Result.mp4 657 KB View Download