Add EXTRA_STREAM_TYPE

This is used to specify the audio stream type to be used by the media
player in TransportControls.playFromMediaId() and
TransportControls.prepareFromMediaId().

Bug: 34700448
Test: ./gradlew updateApi
Change-Id: I9f3136be4e2ddabb4648633a15c34f80418978d3
2 files changed