Chrome Version : 71.0.3549.0 (Official Build) 09b135be6dd0aee298f10cd511efd6574d2edd7f-refs/branch-heads/3549@{#1} 32/64 bit
OS : Windows (7, 8, 8.1)

Test URL : https://tests.peter.sh/notification-generator/

What steps will reproduce the problem?
1. Launch chrome, navigate to above test URL and click on 'Allow' when it asks for notifications permission.
2. Click on 'Display the notification' button seen on the page (notification bubble appears at bottom)
3. Open NTP and observe the notification bubble.

Actual Result : Unable to visually differentiate between NTP page and notification bubble as the border for bubble is not visible.

Expected Result : Notification bubble should have borders such that it can be visible properly on NTP page.

This is a regression issue broken in ‘M-71’ and below is the 'Chromium bisect' information:
Good Build : 70.0.3538.0 (Revision : 587812)
Bad Build : 71.0.3539.0 (Revision : 588235)

Chromium bisect URL :
https://chromium.googlesource.com/chromium/src/+log/ea29e693c42ef0d31fc621813a97dbf6ad72a285..bd5933732c1acc6b426cebfb8d16d32c7a0fc1b9

Suspect : r587960

Tetsui@ : 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.

Note : 
1. This issue is not reproducible in Win-10, Linux(14.04 LTS) and Mac(10.12.6, 10.13.1, 10.14, 10.13.6) OS due to different notification bubble UI.
2. Tried to perform 'per-revision' bisect but it always shows "no enough builds available" error message (tried on different machines but still got the same error.)
3. Hence providing suspect through 'Chromium bisect'.

Thank you..!
 

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