Playback device should broadcast Inactive Source when it does not have

video to broadcast any more

According to the spec, no video to show or standby state should both
trigger Active Source to lose its Acitve state.

We should not only send out inactive source when the device is not
holding a wake lock. Screen can still be turned off with a
PARTIAL_WAKE_LOCK.

Test: manual
Change-Id: I8f9973859ee98a0223cc995610dfb4edc949d57d
(cherry picked from commit bb30a6a99672ecff53ef450889b20db3376fe94c)