[SP21.2] Address comments for API council review about aosp/1172143

This is modified since the shape of API is changed in the
counter-part CL.

Test: atest FrameworksNetTests FrameworksTelephonyTests
Test: atest TetheringTests NetworkStackTests
Fix: 148552904
Change-Id: Idaeb921f6f87c507766566e145838647d47284bd
Merged-In: I1d377ee277e9c21e398d7446b1db28c877cbe6b2
(cherry picked from aosp/1253986)