Disable the software noise suppressor on iOS devices

webrtc/media/engine/webrtcvoiceengine.cc

 /*
  *  Copyright (c) 2004 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 597 matching lines @@
   webrtc::AecmModes aecm_mode = webrtc::kAecmSpeakerphone;
   webrtc::AgcModes agc_mode = webrtc::kAgcAdaptiveAnalog;
   webrtc::NsModes ns_mode = webrtc::kNsHighSuppression;
   if (options.aecm_generate_comfort_noise) {
     LOG(LS_VERBOSE) << "Comfort noise explicitly set to "
                     << *options.aecm_generate_comfort_noise
                     << " (default is false).";
   }
 
 #if defined(WEBRTC_IOS)
-  // On iOS, VPIO provides built-in EC and AGC.
+  // On iOS, VPIO provides built-in EC, NS and AGC.
   options.echo_cancellation = rtc::Optional<bool>(false);
   options.auto_gain_control = rtc::Optional<bool>(false);
-  LOG(LS_INFO) << "Always disable AEC and AGC on iOS. Use built-in instead.";
+  options.noise_suppression = rtc::Optional<bool>(false);
+  LOG(LS_INFO)
+      << "Always disable AEC, NS and AGC on iOS. Use built-in instead.";
 #elif defined(ANDROID)
   ec_mode = webrtc::kEcAecm;
 #endif
 
 #if defined(WEBRTC_IOS) || defined(ANDROID)
   // Set the AGC mode for iOS as well despite disabling it above, to avoid
   // unsupported configuration errors from webrtc.
   agc_mode = webrtc::kAgcFixedDigital;
   options.typing_detection = rtc::Optional<bool>(false);
   options.experimental_agc = rtc::Optional<bool>(false);
@@ skipping 2036 matching lines @@
   RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
   const auto it = send_streams_.find(ssrc);
   if (it != send_streams_.end()) {
     return it->second->channel();
   }
   return -1;
 }
 }  // namespace cricket
 
 #endif  // HAVE_WEBRTC_VOICE