Replace AudioConferenceMixer with AudioMixer.

webrtc/audio/webrtc_audio.gypi

 # Copyright (c) 2013 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.
 {
   'variables': {
     'webrtc_audio_dependencies': [
       '<(webrtc_root)/api/api.gyp:audio_mixer_api',
       '<(webrtc_root)/api/api.gyp:call_api',
       '<(webrtc_root)/common.gyp:webrtc_common',
+      '<(webrtc_root)/common_audio/common_audio.gyp:common_audio',
       '<(webrtc_root)/base/base.gyp:rtc_base_approved',
       '<(webrtc_root)/modules/modules.gyp:audio_device',
       '<(webrtc_root)/modules/modules.gyp:audio_processing',
       '<(webrtc_root)/system_wrappers/system_wrappers.gyp:system_wrappers',
       '<(webrtc_root)/voice_engine/voice_engine.gyp:voice_engine',
       '<(webrtc_root)/webrtc.gyp:rtc_event_log_api',
     ],
     'webrtc_audio_sources': [
       'audio/audio_receive_stream.cc',
       'audio/audio_receive_stream.h',
       'audio/audio_send_stream.cc',
       'audio/audio_send_stream.h',
       'audio/audio_state.cc',
       'audio/audio_state.h',
       'audio/audio_transport_proxy.cc',
       'audio/audio_transport_proxy.h',
       'audio/conversion.h',
       'audio/scoped_voe_interface.h',
     ],
   },
 }