[Cherry pick merge conflict] Updating visibility of some members for easier extensibility

This change is causing a merge conflict with ag/19441591. Hopefully only a cherrypick is needed.

Bug: b/218186980
Test: Manual Testing that Launcher3 compiles and works
Change-Id: Id85486ef763ce9a04b83fef44542b2eb3e0e599d
(cherry picked from commit c487e1b4)