widget: Adding support for custom LockPatternView.

OEMs can overlay the default 9 dots by providing two drawables that represent
those dots:
  * lockscreen_notselected: asset to display when a cell has not been selected.
  * lockscreen_selected: asset to display when a cell has been selected.

BUG: 33755663
Change-Id: Ic595b01f5e1321696b7a3feb0ff73c1acccfb942
5 files changed