Asynchronous handling of remote volume updates

Remote playback information updates will be posted from the
 application thread, and sent to AudioService. Because they
 require locking the stack containing the remote playback
 information, the update should happen on AudioService's handler
 thread to avoid lock contention.

Change-Id: Ie04898295e08c16dd8ab5985fd825301e9cf1981
2 files changed