Comment 0 for bug 1482317

Right now, there are several places we ask USC to turn the screen on when a notification happens:

- powerd for SMS, USSD, and incoming calls
- telephony-service for MMS and telephony messages

And we don't seem to be turning them on for ubuntu-push notifications, but we should, right? Following the pattern above, we'd have ubuntu-push itself turn the screen on, for a third location.

We don't turn the screen on at all for notifications that don't come via those sources. For example, the following command line doesn't turn the screen on, but I think it should:

gdbus call --session --dest org.freedesktop.Notifications --object-path /org/freedesktop/Notifications --method org.freedesktop.Notifications.Notify '' 0 '' 'Hello' 'World' '[]' '{}' 0

I think it feels weird to have telephony-service turning the screen on. Logically, it is just emitting a notification. The presentation of that notification is up to a higher layer (maybe we're on a raspberry pi2 and we emit notifications by LED morse code or whatever). It just makes sense that unity8, which is drawing the notification, is the one that knows that the screen needs to be on. It also knows what form factor we are in (I assume we only want to turn screen on for phones/tablets, not desktops).

So I'm proposing that we unify all those places into one code path in unity8 that can turn the screen on when a notification is received.

(This is a breakout bug from bug 1426115.)