Persist the user's active audio device choice across chromeos session and reboots.

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 7b8d7cc7969676991d6ab8319b0f71a5286f7340..deba1e6487145f261404949c44d083367e0c8f0b 100644
--- a/chromeos/audio/audio_devices_pref_handler.h
+++ b/chromeos/audio/audio_devices_pref_handler.h
@@ -15,20 +15,6 @@ 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.
-// The default value of device state will be AUDIO_STATE_NOT_AVAILABLE if
-// the device is not found in the pref settings.
-// Note that these states enum can't be renumbered or it would break existing
-// preference.
-enum AudioDeviceState {
-  AUDIO_STATE_ACTIVE = 0,
-  AUDIO_STATE_INACTIVE = 1,
-  AUDIO_STATE_NOT_AVAILABLE = 2,
-};
-
 // Interface that handles audio preference related work, reads and writes
 // audio preferences, and notifies AudioPrefObserver for audio preference
 // changes.
@@ -52,9 +38,19 @@ 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;
+  // Sets the device active state in prefs.
+  // Note: |activate_by_user| indicates whether |device| is set to active
+  // by user or by priority, and it only matters when |active| is true.
+  virtual void SetDeviceActive(const AudioDevice& device,
+                               bool active,
+                               bool activate_by_user) = 0;
+  // Returns false if it fails to get device active state from prefs.
+  // Otherwise, returns true, pass the active state data in |*active|
+  // and |*activate_by_user|.
+  // Note: |*activate_by_user| only matters when |*active| is true.
+  virtual bool GetDeviceActive(const AudioDevice& device,
+                               bool* active,
+                               bool* activate_by_user) = 0;
 
   // Reads the audio output allowed value from prefs.
   virtual bool GetAudioOutputAllowedValue() = 0;