Looks like some kind of canonicalization is happening on one side of the DCHECK but not the other. I think it's fine to just remove that DCHECK for now - we're still verifying that account_id and gaia_id match, which should be good enough. blundell@, WDYT?

Thanks for reporting this, Evan, and thanks for looking at it, Marc! Your assessment is correct, Marc. Duping this against crbug.com/842041, which was noticed at basically the same time.

Evan: I'll be looking at fixing this with extremely high priority, but in case I don't get in the fix before you start working again, I think that an even easier workaround should be to just input your email address in the canonical form, unless there's some reason that that would defeat the point of what you're working on/testing.

Re: comment #2, the suggestion there should be "just input the email address that the CHECK is expecting to see".

FWIW, I tried inputting my email in both forms and it hit the same DCHECK.

Oops, thanks for the correction. The issue is whether Gaia's normalized form of the email matches the form in which the user entered it when creating the account. If the answer is no, it doesn't matter how the user enters it when logging into ChromeOS.