base

Battery saver: new policy changes + SystemUI tweaks.

 - Service policy changes: allow the user to turn off (snooze)
   saver mode below the auto-trigger level.  Plugging in the
   device always exits saver mode.
 - Default trigger level is now 0 (never) instead of 15.
 - SystemUI now also listens to a new POWER_SAVE_MODE_CHANGING,
   since waiting for _CHANGED can take seconds.
 - Move shared feature description text into the framework so it
   can be shared.
 - Tweak dialog title + action strings.
 - Remove trigger-level from SystemUI, it no longer needs it.
 - Add the ability to turn off saver mode directly from the
   notification.
 - Migrate saver confirmation dialog to common system UI dialog
   helper, and add a few convenience methods.
 - Fix bug where the status bar area would be orange over the keyguard
   in SHADE_LOCKED mode.

Bug:16214395
Change-Id: I3d1ded1eec9e63e7d97469486f6a320e1bebbccd