Support speaker routing for FLAG_BEACON
Add support for routing audio stream to the speaker when audio
attributes carry the FLAG_BEACON value:
- associate streams with FLAG_BEACON to the up-to-now unused
STREAM_TTS ("Transmitted Through Speaker").
The remapping happens in AudioTrack.
- AudioPolicyManager: define new strategy for handling the Beacon
behavior, that only goes to speaker. Define new volume curves
for STREAM_TTS that are not silence only for the speaker device
category. Keep ref count of other streams and never play Beacon
streams when anything else is playing: either don't start playback
if something else is playing, or unmute STREAM_TTS when it's
allowed to play and mute when it's done.
- Take into account muting latency when starting an output.
Bug 15415971
Change-Id: I26539c7ec1a486accd85bbeb1623e9c7d3a1192f
3 files changed