Lockscreen: Fix SystemUI crash on initial selection of Custom Background.

Change-Id: I8df4984f4b90d211baa888d380a95fc00a85d1ad
Keyguard: more consistency with the new lockscreen wallpaper

* In the case when the screen was off and setCustomDrawable()
was being called, and the use wallpaper is null, then we could be
setting the color filter on a null drawable.

* Fix logic when old custom background was null and the new one is also
null (but could be the user one) and the func was being returned, thus not
clearing out the current media album art.

* Move resetting the shouldShowWallpaper() flag to the show() method
so it is not being called every time the screen is turned on.

* Fix user image not showing up on first boot if it exists

Change-Id: I567c2ec8920df627835defb822c2ea25be7b3cab
Signed-off-by: Roman Birg <roman@cyngn.com>
Keyguard : Fix album art sticking after playback is stopped

newIsNull should be populated by what is currently being set and not by
what the user's custom background is, since otherwise you end up a in state
where the user has no custom background set, music stops, no album art via arg is provided and you simply return.

Change-Id: Ifaea1cae176faaba6b32a711071f3b75ccacdd63
frameworks: move keyguard wallpaper to system  (1/2)

Change-Id: I0eb1b5578b705c2ade4c0772fa86e09478b9f73e
Signed-off-by: Roman Birg <roman@cyngn.com>