Tweak stubs for updatable media

- Add variant for public APIs
- Build against module_current

This is a partial cherry-pick of the CL
I498823de7315f78121975d36d6dc7667a8245085,
which are required by other CLs.

Bug: 147768409
Test: m
Merged-In: I498823de7315f78121975d36d6dc7667a8245085
Change-Id: I811a8a5ff0bda4872ecf7dd62c380fb89a53bf67