Delete deprecated CreateAudioSource method, with constraints.

Bug: webrtc:9239
Change-Id: I5025b7fd103247e0426ceabedc1216a4f0f0ab34
Reviewed-on: https://webrtc-review.googlesource.com/76560
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23501}
diff --git a/examples/peerconnection/client/conductor.cc b/examples/peerconnection/client/conductor.cc
index 746936e..b86ba55 100644
--- a/examples/peerconnection/client/conductor.cc
+++ b/examples/peerconnection/client/conductor.cc
@@ -414,7 +414,8 @@
 
   rtc::scoped_refptr<webrtc::AudioTrackInterface> audio_track(
       peer_connection_factory_->CreateAudioTrack(
-          kAudioLabel, peer_connection_factory_->CreateAudioSource(nullptr)));
+          kAudioLabel, peer_connection_factory_->CreateAudioSource(
+                           cricket::AudioOptions())));
   auto result_or_error = peer_connection_->AddTrack(audio_track, {kStreamId});
   if (!result_or_error.ok()) {
     RTC_LOG(LS_ERROR) << "Failed to add audio track to PeerConnection: "