The set audio routes are used by Telecom to restrict where the audio may be routed to. For example, an account can specify that calls may not be routed over bluetooth headsets, which will prevent a new call from being routed to this source. This is a cherry-pick of abandoned ag/1521009. Bug: 32958838 Change-Id: Idd5e4d38b157f11454f3d991385644f2f384596e