Handle audio node stable device ID change

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 <stdint.h>
 
 #include <map>
@@ skipping 41 matching lines @@
     return (type == AUDIO_TYPE_HEADPHONE ||
             type == AUDIO_TYPE_INTERNAL_MIC ||
             type == AUDIO_TYPE_MIC ||
             type == AUDIO_TYPE_USB ||
             type == AUDIO_TYPE_BLUETOOTH ||
             type == AUDIO_TYPE_HDMI ||
             type == AUDIO_TYPE_INTERNAL_SPEAKER ||
             type == AUDIO_TYPE_LINEOUT);
   }
 
-  bool is_input;
+  bool is_input = false;
 
   // Id of this audio device. The legacy |id| is assigned to be unique everytime
   // when each device got plugged, so that the same physical device will have
   // a different id after unplug then re-plug.
   // The |stable_device_id| is designed to be persistent across system reboot
   // and plug/unplug for the same physical device. It is guaranteed that
   // different type of hardware has different |stable_device_id|, but not
   // guaranteed to be different between the same kind of audio device, e.g
   // USB headset. |id| and |stable_device_id| can be used together to achieve
   // various goals.
-  uint64_t id;
-  uint64_t stable_device_id;
+  // Note that because algorithm used to determine |stable_device_id| changed in
+  // system code, |stable_device_id_version| and |deprecated_stable_device_id|
+  // have been introduced - to ensure backward compatibility until persisted
+  // references to stable device ID have been updated where needed.
+  // |stable_device_id_version| is the version of stable device ID set in
+  // |stable_device_id|. If version is set to 2, |deprecated_stable_device_id|
+  // will contain deprecated, v1 stable device id version.
+  uint64_t id = 0;
+  int stable_device_id_version = 0;
+  uint64_t stable_device_id = 0;
+  uint64_t deprecated_stable_device_id = 0;
   std::string display_name;
   std::string device_name;
   std::string mic_positions;
-  AudioDeviceType type;
-  uint8_t priority;
-  bool active;
-  uint64_t plugged_time;
+  AudioDeviceType type = AUDIO_TYPE_OTHER;
+  uint8_t priority = 0;
+  bool active = false;
+  uint64_t plugged_time = 0;
 };
 
 typedef std::vector<AudioDevice> AudioDeviceList;
 typedef std::map<uint64_t, 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_