Support 4 channel mic in Windows Core Audio

webrtc/modules/audio_device/win/audio_device_core_win.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 314 matching lines @@
     UINT64                                  _writtenSamples;
     LONGLONG                                _playAcc;
 
     UINT                                    _recAudioFrameSize;
     uint32_t                          _recSampleRate;
     uint32_t                          _recBlockSize;
     uint32_t                          _recChannels;
     UINT64                                  _readSamples;
     uint32_t                          _sndCardRecDelay;
 
-    uint16_t                          _recChannelsPrioList[2];
+    uint16_t                          _recChannelsPrioList[3];
     uint16_t                          _playChannelsPrioList[2];
 
     LARGE_INTEGER                           _perfCounterFreq;
     double                                  _perfCounterFactor;
     float                                   _avgCPULoad;
 
 private:
     bool                                    _initialized;
     bool                                    _recording;
     bool                                    _playing;
@@ skipping 23 matching lines @@
     uint16_t                          _newMicLevel;
 
     mutable char                            _str[512];
 };
 
 #endif    // #if (_MSC_VER >= 1400)
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_CORE_WIN_H_