Stop using deprecated constraints-based version of CreateAudioSource.

webrtc/api/mediaconstraintsinterface.h

Index: webrtc/api/mediaconstraintsinterface.h
diff --git a/webrtc/api/mediaconstraintsinterface.h b/webrtc/api/mediaconstraintsinterface.h
index a5d16cb791ba57c266f1beba9dcd69af635fb59e..2017890f62cd54430722aa24118d4517f60d1078 100644
--- a/webrtc/api/mediaconstraintsinterface.h
+++ b/webrtc/api/mediaconstraintsinterface.h
@@ -141,6 +141,11 @@ void CopyConstraintsIntoRtcConfiguration(
     const MediaConstraintsInterface* constraints,
     PeerConnectionInterface::RTCConfiguration* configuration);
 
+// Copy all relevant constraints into an AudioOptions object.
+void CopyConstraintsIntoAudioOptions(
+    const MediaConstraintsInterface* constraints,
+    cricket::AudioOptions* options);
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_MEDIACONSTRAINTSINTERFACE_H_