Stylizing AudioConferenceMixer.

webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer_defines.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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_DEFINES_H_
 #define WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_DEFINES_H_
 
 #include "webrtc/modules/interface/module_common_types.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 class MixHistory;
 
 // A callback class that all mixer participants must inherit from/implement.
 class MixerParticipant
 {
 public:
     // The implementation of this function should update audioFrame with new
     // audio every time it's called.
     //
     // If it returns -1, the frame will not be added to the mix.
-    virtual int32_t GetAudioFrame(const int32_t id, AudioFrame& audioFrame) = 0;
+    virtual int32_t GetAudioFrame(int32_t id,
+                                  AudioFrame* audioFrame) = 0;
 
-    // mixed will be set to true if the participant was mixed this mix iteration
-    int32_t IsMixed(bool& mixed) const;
+    // Returns true if the participant was mixed this mix iteration.
+    bool IsMixed() const;
 
     // This function specifies the sampling frequency needed for the AudioFrame
     // for future GetAudioFrame(..) calls.
-    virtual int32_t NeededFrequency(const int32_t id) = 0;
+    virtual int32_t NeededFrequency(int32_t id) const = 0;
 
     MixHistory* _mixHistory;
 protected:
     MixerParticipant();
     virtual ~MixerParticipant();
 };
 
 class AudioMixerOutputReceiver
 {
 public:
     // This callback function provides the mixed audio for this mix iteration.
     // Note that uniqueAudioFrames is an array of AudioFrame pointers with the
     // size according to the size parameter.
     virtual void NewMixedAudio(const int32_t id,
                                const AudioFrame& generalAudioFrame,
                                const AudioFrame** uniqueAudioFrames,
                                const uint32_t size) = 0;
 protected:
     AudioMixerOutputReceiver() {}
     virtual ~AudioMixerOutputReceiver() {}
 };
 }  // namespace webrtc
 
 #endif // WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_DEFINES_H_