Code review comment for lp:~nick-dedekind/mir/trusted_sessions

I had a quick look at the proposed API; please consider adding an API to add an application by app-id, so that we can add applications which have not been started yet.
More about that here:

https://lists.launchpad.net/ubuntu-phone/msg06680.html

(I myself would have preferred a different approach, where an app could add itself to an existing session)