Remove TODOs that are not needed

Remove TODOs to add classes to the system API that are not needed
(since they are used by a platform-only app).

Bug: 31008728
Test: make droid
Change-Id: I0d75686ddeae929e9d87c5ca8703a609a1450d76
Merged-In: I600e7b08853b86b27463193411cf85207ae09ce8