Replace AudioConferenceMixer with AudioMixer.

webrtc/audio/audio_state.h

Index: webrtc/audio/audio_state.h
diff --git a/webrtc/audio/audio_state.h b/webrtc/audio/audio_state.h
index 31892d04faaa5141b9e25d9486553da4ce101b11..d3c4e5c04feaf50216d50df04a6e77196aa476b7 100644
--- a/webrtc/audio/audio_state.h
+++ b/webrtc/audio/audio_state.h
@@ -11,11 +11,16 @@
 #ifndef WEBRTC_AUDIO_AUDIO_STATE_H_
 #define WEBRTC_AUDIO_AUDIO_STATE_H_
 
+#include <memory>
+
+#include "webrtc/api/audio/audio_mixer.h"
 #include "webrtc/api/call/audio_state.h"
+#include "webrtc/audio/audio_transport_proxy.h"

[the sun, 2016/10/27 10:06:46]

You can get away with forward-declaring the AudioTransportProxy in the .h

[aleloi, 2016/11/01 15:17:35]

Style guide
(https://engdoc.corp.google.com/eng/doc/devguide/cpp/styleguide.shtml?cl=head#...)
says to avoid forward declaration where possible. What do we win by
forward-declaring (compilation speed?)

 #include "webrtc/audio/scoped_voe_interface.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/thread_checker.h"
+#include "webrtc/modules/audio_device/include/audio_device_defines.h"
 #include "webrtc/voice_engine/include/voe_base.h"
 
 namespace webrtc {
@@ -28,6 +33,10 @@ class AudioState final : public webrtc::AudioState,
   ~AudioState() override;
 
   VoiceEngine* voice_engine();
+
+  // The Audio Device currently connected or nullptr.
+  AudioDeviceModule* audio_device();

[the sun, 2016/10/27 10:06:46]

This is an internal util, make it private.

[aleloi, 2016/11/01 15:17:35]

Missed that! I used it previously in audio_receive_stream (hence private) to
make the work of voe->StartPlayout(channel) without connecting the channel to
the old mixer. 

+  rtc::scoped_refptr<AudioMixer> mixer() const;
   bool typing_noise_detected() const;
 
  private:
@@ -53,6 +62,11 @@ class AudioState final : public webrtc::AudioState,
   // Reference count; implementation copied from rtc::RefCountedObject.
   mutable volatile int ref_count_ = 0;
 
+  rtc::scoped_refptr<AudioMixer> mixer_;

[the sun, 2016/10/27 10:06:46]

This should really live in the AudioState::Config, as we ultimately want to make
it settable from the client.

[aleloi, 2016/11/01 15:17:35]

Moved in dependence CL.

+  // Transports mixed audio from the mixer to the audio device and
+  // recorded audio to the VoE AudioTransport.
+  std::unique_ptr<AudioTransportProxy> audio_transport_proxy_;
+
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(AudioState);
 };
 }  // namespace internal