Bug 5045498 API for client to notify remote control info changed

Update to API for a client to notify what type of information
 changed (e.g. playstate, metadata) to optimize small updates
 without the remote control display having to do expensive
 queries such as album art.

When the remote control display retrieves the flags about
 what information changed, the flag gets cleared.

Change-Id: I7d3d8d3eecd1da44695d84905ed9e7b70fe38b86