Add a virtual beamforming audio device on ChromeOS.

chromeos/audio/audio_device.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_AUDIO_AUDIO_DEVICE_H_
 #define CHROMEOS_AUDIO_AUDIO_DEVICE_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 45 matching lines @@
   }
 
   bool is_input;
   uint64 id;
   std::string display_name;
   std::string device_name;
   AudioDeviceType type;
   uint8 priority;
   bool active;
   uint64 plugged_time;
+  std::string mic_positions;
 };
 
 typedef std::vector<AudioDevice> AudioDeviceList;
 typedef std::map<uint64, AudioDevice> AudioDeviceMap;
 
 struct AudioDeviceCompare {
   // Rules used to discern which device is higher,
   // 1.) Device Type:
   //       [Headphones/USB/Bluetooh > HDMI > Internal Speakers]
   //       [External Mic/USB Mic/Bluetooth > Internal Mic]
   // 2.) Device Plugged in Time:
   //       [Later > Earlier]
   bool operator()(const chromeos::AudioDevice& a,
                   const chromeos::AudioDevice& b) const {
     if (a.priority < b.priority) {
       return true;
     } else if (b.priority < a.priority) {
       return false;
     } else if (a.plugged_time < b.plugged_time) {
       return true;
     } else {
       return false;
     }
   }
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_AUDIO_AUDIO_DEVICE_H_