Store audio device's active state in preference

chromeos/audio/audio_devices_pref_handler.h

Index: chromeos/audio/audio_devices_pref_handler.h
diff --git a/chromeos/audio/audio_devices_pref_handler.h b/chromeos/audio/audio_devices_pref_handler.h
index dfa582e4e57de1bcb6e7e4e88876acefd892456a..e80dc2c5adcc298de5432bd27b71c900dd547863 100644
--- a/chromeos/audio/audio_devices_pref_handler.h
+++ b/chromeos/audio/audio_devices_pref_handler.h
@@ -16,6 +16,18 @@ namespace chromeos {
 
 struct AudioDevice;
 
+// Used to represent an audio device's state. This state should be updated
+// to AUDIO_STATE_ACTIVE when it is selected as active or set to
+// AUDIO_STATE_INACTIVE when selected to a different device. When the audio
+// device is unplugged, its last active/inactive state should be stored.
+// At the first time an audio device got plugged, use AUDIO_STATE_NOT_AVAILABLE
+// as its default state value.

[jennyz, 2015/12/17 22:50:21]

Any specific reason to use AUDIO_STATE_NOT_AVAILABL when an audio device got
plugged for the first time? It seems confusing without any further comments.

[hychao, 2015/12/29 10:57:25]

Updated as you suggested in another comment. Thanks!

+enum AudioDeviceState {
+  AUDIO_STATE_ACTIVE,
+  AUDIO_STATE_INACTIVE,
+  AUDIO_STATE_NOT_AVAILABLE,
+};
+
 // Interface that handles audio preference related work, reads and writes
 // audio preferences, and notifies AudioPrefObserver for audio preference
 // changes.
@@ -39,6 +51,11 @@ class CHROMEOS_EXPORT AudioDevicesPrefHandler
   // Sets the audio mute value to prefs for a device.
   virtual void SetMuteValue(const AudioDevice& device, bool mute_on) = 0;
 
+  virtual AudioDeviceState GetDeviceState(
+      const AudioDevice &device) = 0;
+  virtual void SetDeviceState(const AudioDevice& device,
+                              AudioDeviceState state) = 0;
+
   // Reads the audio output allowed value from prefs.
   virtual bool GetAudioOutputAllowedValue() = 0;