Remove dependency on AudioStub in ConnectionToClient

remoting/protocol/webrtc_connection_to_client.h

Index: remoting/protocol/webrtc_connection_to_client.h
diff --git a/remoting/protocol/webrtc_connection_to_client.h b/remoting/protocol/webrtc_connection_to_client.h
index 07e7d1e537bf0c7da519e0fd754e62b990ac182e..34bf1f16bc0788f264626640b724f7e70a8a3dec 100644
--- a/remoting/protocol/webrtc_connection_to_client.h
+++ b/remoting/protocol/webrtc_connection_to_client.h
@@ -43,7 +43,8 @@ class WebrtcConnectionToClient : public ConnectionToClient,
   void OnInputEventReceived(int64_t timestamp) override;
   std::unique_ptr<VideoStream> StartVideoStream(
       std::unique_ptr<webrtc::DesktopCapturer> desktop_capturer) override;
-  AudioStub* audio_stub() override;
+  std::unique_ptr<AudioSendStream> StartAudioStream(
+      std::unique_ptr<AudioSource> audio_source) override;
   ClientStub* client_stub() override;
   void set_clipboard_stub(ClipboardStub* clipboard_stub) override;
   void set_host_stub(HostStub* host_stub) override;