AVRCP: Fix for audio leak to speaker when BT dev is set active

Some remote devices send avrcp play soon after connection and
if it is a first a2dp connection, AVRCP PT cmd is dispatched
to MediaSessionService. Streaming will be started before
output device is changed to bt_a2dp resulting in momentary
audio leak to speaker. To avoid playback start before active
device is updated, cache avrcp play passthrough command if
a2dp active device is null and process play cmd when
onAudioDeviceAdded callback is received from MM audio.

Change-Id: I37bb628d2f485910701558e162cf0e0d667d9965
1 file changed