[ConsoleKit] [gdm-list] Reworked patch for multi-seat and multi-display support

[Ray Strode]

Hey,

> I saw you commit the second patch into branch multi-seat. Apparently,
> you missed adding folder data/displays.d.
> http://cgit.freedesktop.org/ConsoleKit/tree/data?h=multi-seat
>
> Can I add that folder and get pushed?
Sure, that branch is yours to do what you want with.
Sorry about forgetting the display files.  I had it fixed locally but
didn't push yet,
I've fixed it now.

> BTW, fatal told me you're reviewing the changes last week, would you
> please share your status?

Still working on it, I want to finish up and give a mail with the
changes I'm making.

It's a bit more work than I thought it would be. I'll go in more depth
when I've tied a few more loose ends, but most of the consolekit
changes are:

1) sort seat files so they're loaded in a deterministic order
2) add a new "session" file which bridges seats to display types
3) add the new dbus messages to dbus security policy so they aren't
blocked by the bus daemon
4) make GetUnmanagedSeats only return unmanaged seats
5) make seats deal strictly with sessions, not dsplays.  in
user-switching world one seat can have multiple sessions/displays
6) only load display types from disk once, not once per use
7) drop priority property from display type
8) make SessionToAdd/SessionToRemove be more generic so they aren't X specific
9) add an UnmanageSeat method so display managers can give up on a seat
10) Split CreateSession into two functions: one that creates a seat,
and one that creates a session on the seat.

I'll follow up with a rationale for the changes and a link to the
changes when i've finished things up.

--Ray