Avoid layout passes when updating data activity indicators.

ImageView can optimize out layout passes if old and new drawable have
equal sizes. Take advantage of that by displaying a transparent drawable
with the same size as the in/out drawables when there's no activity
instead of clearing out the drawable in that case.

Restoring file and setting the difference

Trying to exclude the java file

Change-Id: Iaaa556ffab3ed4be1da8016ed40d0a9c2efcde01
Bring back the status bar activity indicators for mobile data and wifi

Google were nice enough to create xxhdpi drawables for us before removing them.

Reverts "Remove signal/wifi activity indicator icon overlays."

This reverts commit fcc901c10bffdfb9c6b31e676dec36b47d949979.

Included NetworkController.java modification from Iaaa556ffab3ed4be1da8016ed40d0a9c2efcde01

Change-Id: I7aa85f7c8442c45d17e42cac7823dfe93e3f24c1
Quicksettings: Few misc adjustements and fixes.

* Fix sleep time tile label on clean flash boot, was showing unknown till you set it in settings.
  Initialize screen timeout with default 30 seconds (wrongly initialized with 0 that is never compared).
* Use switch statement (better performance wise).
* Bit cleanup for wifi ap tile, useless resources reload.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>