Revert "Remove abandoned implementation."

Revert submission 3242160-remove-messaging-package

Reason for revert: Droidmonitor created revert due to b/364617310, b/364626927, b/364617560

Reverted changes: /q/submissionid:3241481-remove-messaging-package

This reverts commit 93b5e63726ab8f47a8266ed1cccf7c9c281bf0e0.

Change-Id: I182cbf1758988d9a4950d39354266a5fb3aaabce
1487 files changed