Companion InCallService API review

Test: atest; make docs
Bug: 179116441
Change-Id: Id75e727f6c3fc42132a80f7258bf790be79acf19
Merged-In: Id75e727f6c3fc42132a80f7258bf790be79acf19
(cherry picked from commit d30bd60beb6e098b279ccb4a839c7ad89a1b6c64)
4 files changed