Comment 2 for bug 1208640

Are you summarizing the suggestion Haneef, or summarizing what is currently implemented? I think it's the former. A TLDR of my proposal is a good idea... here goes:

* A project token remains scoped to a project, as in V2
* V3 introduces domain tokens, which are scoped to a domain
* We remove unscoped tokens from V3
* In the rare case where you would get an unscoped token in V3, you get a domain token instead.
* When a V2 client requests an unscoped token, they just get a domain token instead. V2 clients can't tell the difference.