DO NOT MERGE update play status based on A2dp audio state from stack.

this is to work around the problem:some video/audio player didn't
update the play status by calling setPlaybackState.
The headset(HBS730) register the play status update on the phone.
It will depend the play status reported from the phone to send
play or pause command.

bug:11325212
Change-Id: I7fde5960edd4a5b3474fa17456aacd5b4b432d4d