Add an internal API to get all asset locales.

This will allow us to not copy paste this code verbatim into
bundled apps.

bug: 10090157

(cherry picked from commit 9e6d9d4c812d01ac07180c5d6ab64c36fb9b2aa7)

Change-Id: I34690a2b6dad51f1592f37d3c2a8c81345632c2f
1 file changed