Check for null when getting PiP action item drawables.

Upon loading the action item drawables, it's possible they end up
returned as null.

Bug: 167338598
Test: None
Merged-In: Iff2b7d499cee275294075a37a4970dc2dbc97401
Change-Id: Iff2b7d499cee275294075a37a4970dc2dbc97401
(cherry picked from commit e09e8e8a182a9795dbbad78c41e1aea2be387425)
1 file changed