Add ActiveSouce handling logic to switch to ARC input
when the new Active is not under the current device.

ag/4958795

Note that this CL only handles automatically switching to ARC.
Switching back to HOME should be handled by SetStreamPath or RoutingChange.

Test: local test.

Bug: 112476228
Change-Id: I211130c9483be7fcfe55b6a57f43d82bcf319737
5 files changed