Allow an external audio processing module to be used in WebRTC

webrtc/api/peerconnectioninterface.h

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 1145 matching lines @@
 //
 // If |network_thread| or |worker_thread| are null, the PeerConnectionFactory
 // will create the necessary thread internally. If |signaling_thread| is null,
 // the PeerConnectionFactory will use the thread on which this method is called
 // as the signaling thread, wrapping it in an rtc::Thread object if needed.
 //
 // If non-null, a reference is added to |default_adm|, and ownership of
 // |video_encoder_factory| and |video_decoder_factory| is transferred to the
 // returned factory.
 //
+// If |audio_mixer| is null, an internal audio mixer will be created and used.
+//
 // TODO(deadbeef): Use rtc::scoped_refptr<> and std::unique_ptr<> to make this
 // ownership transfer and ref counting more obvious.
 //
 // TODO(deadbeef): Encapsulate these modules in a struct, so that when a new
 // module is inevitably exposed, we can just add a field to the struct instead
 // of adding a whole new CreateModularPeerConnectionFactory overload.
 rtc::scoped_refptr<PeerConnectionFactoryInterface>
 CreateModularPeerConnectionFactory(
     rtc::Thread* network_thread,
     rtc::Thread* worker_thread,
     rtc::Thread* signaling_thread,
     AudioDeviceModule* default_adm,
     rtc::scoped_refptr<AudioEncoderFactory> audio_encoder_factory,
     rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory,
     cricket::WebRtcVideoEncoderFactory* video_encoder_factory,
     cricket::WebRtcVideoDecoderFactory* video_decoder_factory,
     rtc::scoped_refptr<AudioMixer> audio_mixer,
     std::unique_ptr<cricket::MediaEngineInterface> media_engine,
     std::unique_ptr<CallFactoryInterface> call_factory,
     std::unique_ptr<RtcEventLogFactoryInterface> event_log_factory);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_PEERCONNECTIONINTERFACE_H_