Unity: thumbnails for running apps are not cached

[Pat McGowan]

saucy-19
gnex and nexus 4

If you select the app to display it again, the lens will once again show the correct images.

[Michał Sawicz (saviq)]

Can you post some more steps to reproduce?

If they are:

* launch an app
* start a long-drag from the left, but don't release
* release after a second or two

The reason is that the app is being unfocused before it's ever drawn its UI, it gets unfocused and the shell doesn't request new screenshots of the app while it's unfocused. We could probably improve this situation by requesting screenshots at unfocus, too.

We'll also need to cache those screenshots for later use (when app gets killed or as a splash screen when it's launching).

[Michał Sawicz (saviq)]

Steps to reproduce:

* start some apps
* go to apps scope
* search
* reset search

All the app snapshots are black, 'cause the apps are unfocused (hence probably stopped), so there's no way to get a snapshot of them. We need to cache the snapshots on disk, and also Mir should help here, because it should hold the last uploaded texture and we should be able to get to it.

[kevin gunn (kgunn72)]

albert - wonder if you might be able to help gerry out here
looks like this will need to be a phone v1 target
(even tho pat wanted it to be medium ;) just kidding pat)

[Albert Astals Cid (aacid)]

Reassigning to Michał since he convinced me on IRC that this bug "is done" and what's actually missing are two different things from the one reported here

[Michał Sawicz (saviq)]

I meant that the bigger issue here (the original "app screenshots are black") is fixed with unity-mir. We still have the case when the application is killed that's probably not handled, but that's not something we should focus on for v1, IMO.

[Michael Hall (mhall119)]

Attaching a screenshot of what I have on Trusty r28

Terminal has a running process still, but uReadIt does not.

Google+ and GMail do not have running webbrowser-app processes.

[Michael Hall (mhall119)]

Attaching unity8.log from the phone