Reland of move ignored return code from modules.

webrtc/modules/audio_conference_mixer/include/audio_conference_mixer.h

 /*
  *  Copyright (c) 2011 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 22 matching lines @@
         kLowestPossible   = -1,
         kDefaultFrequency = kWbInHz
     };
 
     // Factory method. Constructor disabled.
     static AudioConferenceMixer* Create(int id);
     virtual ~AudioConferenceMixer() {}
 
     // Module functions
     int64_t TimeUntilNextProcess() override = 0;
-    int32_t Process() override = 0;
+    void Process() override = 0;
 
     // Register/unregister a callback class for receiving the mixed audio.
     virtual int32_t RegisterMixedStreamCallback(
         AudioMixerOutputReceiver* receiver) = 0;
     virtual int32_t UnRegisterMixedStreamCallback() = 0;
 
     // Add/remove participants as candidates for mixing.
     virtual int32_t SetMixabilityStatus(MixerParticipant* participant,
                                         bool mixable) = 0;
     // Returns true if a participant is a candidate for mixing.
@@ skipping 14 matching lines @@
     // may still choose to mix at a higher samling frequency to avoid
     // downsampling of audio contributing to the mixed audio.
     virtual int32_t SetMinimumMixingFrequency(Frequency freq) = 0;
 
 protected:
     AudioConferenceMixer() {}
 };
 }  // namespace webrtc
 
 #endif // WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INCLUDE_AUDIO_CONFERENCE_MIXER_H_