Use CompletableFuture instead of a latch.

Addresses review comments on aosp/1260100.

Bug: 150644681
Test: test-only change
Merged-In: Ia73ba8a121a3744a5e36795d2d2bff2f099c1394
Change-Id: Ia73ba8a121a3744a5e36795d2d2bff2f099c1394
1 file changed
tree: 9b6a9af3a0607749a1b10a934ac24038c0db7163
  1. Tethering/