Remove unnecessary audio references in PeerConnectionFactory

sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm

 /*
  *  Copyright 2015 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 92 matching lines @@
     NSAssert(result, @"Failed to start worker thread.");
 
     _signalingThread = rtc::Thread::Create();
     result = _signalingThread->Start();
     NSAssert(result, @"Failed to start signaling thread.");
 #ifdef HAVE_NO_MEDIA
     _nativeFactory = webrtc::CreateModularPeerConnectionFactory(
         _networkThread.get(),
         _workerThread.get(),
         _signalingThread.get(),
-        nullptr,  // default_adm
-        nullptr,  // audio_encoder_factory
-        nullptr,  // audio_decoder_factory
         nullptr,  // video_encoder_factory
         nullptr,  // video_decoder_factory
-        nullptr,  // audio_mixer
         std::unique_ptr<cricket::MediaEngineInterface>(),
         std::unique_ptr<webrtc::CallFactoryInterface>(),
         std::unique_ptr<webrtc::RtcEventLogFactoryInterface>());
 #else
     // Ownership of encoder/decoder factories is passed on to the
     // peerconnectionfactory, that handles deleting them.
     _nativeFactory = webrtc::CreatePeerConnectionFactory(_networkThread.get(),
                                                          _workerThread.get(),
                                                          _signalingThread.get(),
                                                          nullptr,  // audio device module
@@ skipping 88 matching lines @@
   _hasStartedAecDump = _nativeFactory->StartAecDump(fd, maxSizeInBytes);
   return _hasStartedAecDump;
 }
 
 - (void)stopAecDump {
   _nativeFactory->StopAecDump();
   _hasStartedAecDump = NO;
 }
 
 @end