Fix the comments from aosp/1719018

1. Test {start,stop}-service
2. Add waitForIdle

Bug: 181810560
Test: atest NsdServiceTest
Original-Change: https://android-review.googlesource.com/1729691
Merged-In: I0953887d1d92a644a29a2e80521469c8cc2aa2fc
Change-Id: I0953887d1d92a644a29a2e80521469c8cc2aa2fc
1 file changed