Navbar: handle images selected through the documents api

4.4 added a unified documents api to choose media files. Handle
the returnd data.

Change-Id: I0ecba27ce120ad63abad33aec5364ef00795de3c
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>
Merge "Navbar: handle images selected through the documents api" into kitkat