Chrome Version       : 57.0.2979.0 (Developer Build) (32-bit)

TL;DR for people sorting/labelling this - this is about a UX conflict between Chrome's new multiple sign-in and a Docs/Drive limitation. I think that the Chrome signin and Docs/Drive teams will need to talk with each other about this issue, so it may need to be routed/linked/forwarded to other internal trackers.

I'm not sure when the two flags I mention below in (1) landed, but I know that the Chrome version listed above (and presumably any later version) has them.

What steps will reproduce the problem?
(1) Enable the new multiple Google account sign-in support by turning on "Identity consistency between browser and cookie jar" and "Enable new gaia password-separated sign in flow" in about:flags - it's either one or both of those (I'm not 100% sure).
(2) Be signed into at least two Google accounts *all using the same domain* (@gmail.com, @google.com, etc) - you can (now) do this directly by clicking the user profile dropdown in Chrome itself, clicking "Your accounts", then "Add account for ..."
(3) Go to docs.google.com
(4) Click your user profile icon at the top-right and select any account other than the active one *that uses the same ending as the active one*
(5) You'll see a page showing "Choose an account to use with Google Drive" and listing all your accounts, but all the accounts on the same domain as the first account you signed into (the one shown in Google product URLs as /u/0) will be greyed-out and say "Unavailable unless you sign out of all other Google Accounts and then sign in to this one."
(6) Clicking any of the "sign out" links will pop up Chrome's new account selector.
(7) Now disable the two flags you enabled in (1), and repeat steps 3-5. This time, clicking one of the "sign out" links will run you through the nuke-all-logins-from-orbit flow so you can login from scratch again.


What is the expected result?

Now that Chrome is sending a clear message of seamless support for multiple Google account sign-in, Google Docs'/Google Drive's inability to handle more than one login from the same domain may introduce friction with some users (particularly the majority using Gmail) who want to sign-in to all their accounts and keep that in Sync then discover they can't keep that info in Chrome and also use Docs.


What happens instead?

The intersection of Google Docs/Google Drive users who are also using multiple Google accounts on the same domain will be unable to also use this new Chrome feature, because Docs/Drive will force them to remove all their signed-in accounts from Chrome.


Please provide any additional information below. Attach a screenshot if
possible.

This issue's intent is to connect the two datapoints "Chrome expressly advertises multiple logins and encourages this as a supported idea" and "Docs explicitly does NOT support multiple logins on the same domain".

When on the "Select an account..." page, the error message text (if you could call it that) has a link, "Other options". That leads to https://support.google.com/docs/answer/2405894 (via https://support.google.com/docs?p=switch_accounts_error), which explicitly states that Docs does not support multiple accounts on the same domain.

For me personally, it's annoying that editing Docs stuff on different Google accounts requires me to maintain multiple Chrome profiles or use incognito mode, but now that Chrome natively handles multiple accounts it feels even more imbalanced/inconsistent that Docs has this shortcoming.

I discovered the new multiple-signon system after trundling through about:flags about a week ago and enabling a bunch of new stuff that looked interesting (since I like to live dangerously :P). Then I noticed that I'd been signed out, and when I went to sign back in saw how "Add account" etc in the SSO account-selector menu on google.com had switched to "Manage accounts", and clicking that [element inside the webpage on google.com] popped up Chrome's new native-UI account selector. (Nice.)

It's clear that a _lot_ of work has gone into designing and building this new feature and I wanted to extend my appreciation to the multiple team(s) who got this shipped - I get the impression I'm not the only one who has wanted this for some time! This is obviously the direction Google wants to go in; even google.com itself (or more accurately the SSO framework exposed everywhere including on google.com) has been integrated with the new functionality.

Considering the amount of effort that has been made, it seems to me like there might be some momentum that could be latched onto to justify getting Docs supporting multiple accounts on the same domain. Users with the above flags enabled *can* continue to use Docs with multiple profiles or incognito, but it's obvious there's a push towards "sign in to Chrome with one account and everything shows up," and this just seems inconsistent with that.

It's awesome that this new functionality is available and that it syncs everything to my Google account. Security ramifications (which have obviously been considered) notwithstanding, I love the convenience.

If it's decided that this is not viable (which would be very very sad), I think the UX behavior of "user clicks signout link, random popup appears - on the other side of the screen" could do with a bit of critique; it feels a bit raw/unfinished at the moment. This happens in (6) in the repro info above.

I'm filing this here instead of in the Docs/Drive forum on the technicality that this does relate to new behavior in Chrome. I recognize that this is not a Chrome bug in the traditional sense (to be clear, Chrome's new signin flow is working perfectly). However, unlike the product forums, this tracker is monitored almost entirely by engineers and puts issues that bit closer to the teams that can fix them. Hopefully filing this here was okay; should I use the product forums next time?

I realize this issue will likely not end up being tracked on here, but I'm very interested to know how it works out! :)

Also - from a technical standpoint, the account-switcher "error" page talks about Drive, but it's Docs that has the actual limitation, right? And I take it that Docs was only architected to distinguish between domains, and not accounts...? I've admittedly been curious as to the historical reasons for this for a while.