Merge changes from topics "LWBS-master", "fused_location-master"

* changes:
  Add battery-saver and combined-location Setting keys to backup test
  Rename PLAY_STORE_AVAILABILITY with PHONE_PLAY_STORE_AVAILABILITY.
  Add new key to System Content Provider for combined location
  Move KEY_BURN_IN_PROTECTION to Settings.Global
  [Ambient Lite] Add a WEAR_ACTIVITY_AUTO_RESUME_TIMEOUT_MS setting.
  Add new keys to Settings Content Provider for Battery Saver