Return TTS result AFTER action has been completed

When NotificationClickHandlerFactory calls CarAssistUtils.request...Action(),
it should have a mechanism to understand when the action has been completed
(i.e. message has been read aloud). Change the CarAssistUtils API to
take in a callback (similar to it's Q impl), and trigger it after TTS and/or
Assistant have finished the action.

Change-Id: Ia91b32824ff45c8cb47175072ae6af07b7ec9c3f
Fix: 131363906
Test: manual
2 files changed
tree: fca0145d923bffd79d3e82a217e6f886270c934f
  1. car-assist-client-lib/
  2. car-broadcastradio-support/
  3. OWNERS
  4. PREUPLOAD.cfg