Icon support comes to Notification.

  And you may ask yourself: what is that beautiful icon?
  And you may ask yourself: where does that API go to?
  And you may ask yourself: is it a resource? is it a Bitmap?
  And you may say to yourself: my god, what have I done

Bug: 18568715
Change-Id: I4377b311c538bd1cf36b3fba22326bae81af40c9