Update sharesheet owners

- Update owners to chooser subdir.
- Add missing per-file in sharesheet implementation.

Test: presubmits
Bug: N/A
Change-Id: I4e1b5246790ed677729adacfb0f7d63c700b29c1
(cherry picked from commit 80f927d49b2441084675d4173d00d249250979e4)
Merged-In: I4e1b5246790ed677729adacfb0f7d63c700b29c1
2 files changed