Chrome Version : 64.0.3282.0 (Official Build) 5fdc0fab22ce7efd32532ee989b223fa12f8171e-refs/heads/master@{#520840} 64-bit
OS : Mac(10.12.6) (10.13.2)

What steps will reproduce the problem?
1. Launch chrome, open NTP and press ‘Cmd + Shift + M’ keys to open profile chooser.
2. Press ‘Tab’ key to bring focus on ‘Guest’ option, hit ‘Enter’ and observe.

Actual Result : Unable to select ‘Guest’, ‘Manage people’  options under ‘Profile chooser’ dialog through ‘Enter’ key.

Expected Result : User should be able to access ‘Guest’, ‘Manage people’ options through ‘Enter’ key.

This is a regression issue broken in ‘M-64’ and using the per-revision bisect providing the bisect results,
Good build : 64.0.3264.0 (Revision : 515410)
Bad build : 64.0.3265.0 (Revision : 515780)

You are probably looking for a change made after 515522 (known good), but no later than 515523 (first known bad).

CHANGELOG URL:
https://chromium.googlesource.com/chromium/src/+log/a63b2ddd636c62a3fe3f5e46c6c951e9fce23993..ff683d4c68b0505229fe56d1bd34e371f1758124

Suspect : https://chromium.googlesource.com/chromium/src/+/ff683d4c68b0505229fe56d1bd34e371f1758124

@jlebel : Could you please look into the issue, pardon me if it has nothing to do with your changes and if possible please assign it to concern owner.

Notes : 
1. This issue is observed on Mac Mini(10.12.6) & Mac Touch bar(10.13.2) machines.
2. Above issue is not observed on Windows(7,8,10) & Linux(14.04 LTS) OS.
 

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