So apparently the CL commit description got commited only to the linked b/66994755 (because I didn't open this bug yet or link it on the CL). Any way to fix that? Here's a link to the cl crrev.com/c/764147

Anyway, I'd like to merge this to M63 as it's affecting a customer (and possibly others who didn't bother reporting). I hope it works, but I also understand if it's too late in the process for that.

This bug requires manual review: M63 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), gkihumba@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

I would target M64 for this as we're 3 weeks away from stable.

Gotcha! Thanks for taking a look.

Adding RBB label for verification so it's on TPM radar

Verified fixed. Whitelisted extension is honoring correctly in Public Session.

Public session configuration:
1. Add User-Agent Switcher for Chrome (ID: djflhoibgkdhkhhcedjiklpkjnoahfmg) in Device management > Chrome management > Public session settings > Force-installed Apps and Extensions
2. Upload a configuration json file in Chrome management > App management > User-Agent Switcher for Chrome > Public session settings
   uploaded Customer example file: https://drive.google.com/open?id=0B01ZVp8vDQocNUhvV08xTTZuNXc
3. Enable Public session kiosks in Chrome management > Device settings
4. Restart the managed device and check chrome://policy
5. Go to whatsmyuseragent.org (S=107 IS added)

Chrome OS: 10452.1.0
Chrome: 66.0.3359.10
Device: Santa