Removed the memory pool from the mixer.

webrtc/modules/audio_mixer/include/audio_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_MIXER_INCLUDE_AUDIO_MIXER_DEFINES_H_
 #define WEBRTC_MODULES_AUDIO_MIXER_INCLUDE_AUDIO_MIXER_DEFINES_H_
 
 #include "webrtc/base/checks.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 class NewMixHistory;
 
 // A callback class that all mixer participants must inherit from/implement.
 class MixerAudioSource {
  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.
-  //
-  // NOTE: This function should not be called. It will remain for a short
-  // time so that subclasses can override it without getting warnings.
-  // TODO(henrik.lundin) Remove this function.
-  virtual int32_t GetAudioFrame(int32_t id, AudioFrame* audioFrame) {
-    RTC_CHECK(false);
-    return -1;
-  }
 
-  // The implementation of GetAudioFrameWithMuted should update audio_frame
-  // with new audio every time it's called. The return value will be
-  // interpreted as follows.
   enum class AudioFrameInfo {
     kNormal,  // The samples in audio_frame are valid and should be used.
     kMuted,   // The samples in audio_frame should not be used, but should be
               // implicitly interpreted as zero. Other fields in audio_frame
               // may be read and should contain meaningful values.
     kError    // audio_frame will not be used.
   };
 
-  virtual AudioFrameInfo GetAudioFrameWithMuted(int32_t id,
-                                                AudioFrame* audio_frame) {
-    return GetAudioFrame(id, audio_frame) == -1 ? AudioFrameInfo::kError
-                                                : AudioFrameInfo::kNormal;
-  }
+  struct AudioFrameWithInfo {
+    AudioFrame* audio_frame_pointer;

[ossu, 2016/07/06 12:58:44]

I think this should just be called audio_frame (without the _pointer). I can't
find us explicitly calling out a thing is a pointer like this almost anywhere
else in the source.

+    AudioFrameInfo audio_frame_info;
+  };
+
+  // The implementation of GetAudioFrameWithMuted should update
+  // audio_frame with new audio every time it's called. Implementing
+  // classes are allowed to return the same AudioFrame pointer on
+  // different calls.
+  virtual AudioFrameWithInfo GetAudioFrameWithMuted(int32_t id,
+                                                    int sample_rate_hz) = 0;
 
   // 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(int32_t id) const = 0;
 
   NewMixHistory* _mixHistory;
 
  protected:
   MixerAudioSource();
   virtual ~MixerAudioSource();
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_MIXER_INCLUDE_AUDIO_MIXER_DEFINES_H_