Revert of Rewrote UpdateToMix in the audio mixer.

webrtc/modules/audio_mixer/source/new_audio_conference_mixer_impl.h

 /*
  *  Copyright (c) 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 66 matching lines @@
   void Mix(AudioFrame* audio_frame_for_mixing) override;
   int32_t SetMinimumMixingFrequency(Frequency freq) override;
   bool AnonymousMixabilityStatus(
       const MixerAudioSource& audio_source) const override;
 
  private:
   // Set/get mix frequency
   int32_t SetOutputFrequency(const Frequency& frequency);
   Frequency OutputFrequency() const;
 
-  // Compute what audio sources to mix from audio_source_list_. Ramp in
-  // and out. Update mixed status. maxAudioFrameCounter specifies how
-  // many participants are allowed to be mixed.
-  AudioFrameList UpdateToMix(size_t maxAudioFrameCounter) const;
+  // Fills mixList with the AudioFrames pointers that should be used when
+  // mixing.
+  // maxAudioFrameCounter both input and output specifies how many more
+  // AudioFrames that are allowed to be mixed.
+  // rampOutList contain AudioFrames corresponding to an audio stream that
+  // used to be mixed but shouldn't be mixed any longer. These AudioFrames
+  // should be ramped out over this AudioFrame to avoid audio discontinuities.
+  void UpdateToMix(AudioFrameList* mixList,
+                   AudioFrameList* rampOutList,
+                   std::map<int, MixerAudioSource*>* mixAudioSourceList,
+                   size_t* maxAudioFrameCounter) const;
 
   // Return the lowest mixing frequency that can be used without having to
   // downsample any audio.
   int32_t GetLowestMixingFrequency() const;
   int32_t GetLowestMixingFrequencyFromList(
       const MixerAudioSourceList& mixList) const;
 
   // Return the AudioFrames that should be mixed anonymously.
   void GetAdditionalAudio(AudioFrameList* additionalFramesList) const;
 
+  // Update the NewMixHistory of all MixerAudioSources. mixedAudioSourcesList
+  // should contain a map of MixerAudioSources that have been mixed.
+  void UpdateMixedStatus(
+      const std::map<int, MixerAudioSource*>& mixedAudioSourcesList) const;
+
   // Clears audioFrameList and reclaims all memory associated with it.
   void ClearAudioFrameList(AudioFrameList* audioFrameList) const;
 
   // This function returns true if it finds the MixerAudioSource in the
   // specified list of MixerAudioSources.
   bool IsAudioSourceInList(const MixerAudioSource& audio_source,
                            const MixerAudioSourceList& audioSourceList) const;
 
   // Add/remove the MixerAudioSource to the specified
   // MixerAudioSource list.
@@ skipping 42 matching lines @@
 
   // Ensures that Mix is called from the same thread.
   rtc::ThreadChecker thread_checker_;
 
   // Used for inhibiting saturation in mixing.
   std::unique_ptr<AudioProcessing> _limiter;
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_MIXER_SOURCE_NEW_AUDIO_CONFERENCE_MIXER_IMPL_H_