What steps will reproduce the problem?
1. Have multiple accounts, e.g. @google.com, @gmail.com, @chromium.org
2. Be accidentally only signed into one of them, e.g. @google.com
3. Visit codereview.chromium.org and sign in

What is the expected result?
Prompted to either create a new account or switch to another account.

What happens instead of that?
New codereview.chromium.org account created with @google.com account. ARG. Now I have to delete that account, which signs out all accounts.