Update API files to unhide MATCH_PROXY.

Bug: 204830222
Test: m
Ignore-AOSP-First: part of topic with internal-only code
  (cherry-picked from ag/16786006)
Change-Id: I9e11eea30ea9c988498e005c33f173ba2d0a32ec
Merged-In: I9e11eea30ea9c988498e005c33f173ba2d0a32ec
1 file changed