RESTRICT AUTOMERGE Prevent accessing companion records from arbitrary uids Relanding after previous revert. Test: manual Bug: 129476618 Bug: 158576209 Change-Id: I4f7dc13067ab4aa4f0c3f5373ee0a28c0285eea1 (cherry picked from commit 4f7dc13067ab4aa4f0c3f5373ee0a28c0285eea1)