Copy 28.txt in master.

28.txt is different in pi-dev and master, so the automerged
android.txt from I736cd36f0f3ad46c88f65541f4a58d5bd7c8efac
doesn't match the 28.txt in master.

This works around b/78507631, and unblocks my other change
I54989816ea09ad7a1e2f2355926678e6d2edb27c. I'll re-do this copy
(in some branch) once the bug is resolved.

Test: diff api/28.txt 28/public/api/android.txt is empty.
Bug: 78507631
Change-Id: I049736a4eff88258ef82ceb414980a4f8b8387a6
1 file changed