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

chromeos/dbus/fake_cras_audio_client.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_DBUS_FAKE_CRAS_AUDIO_CLIENT_H_
 #define CHROMEOS_DBUS_FAKE_CRAS_AUDIO_CLIENT_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
@@ skipping 22 matching lines @@
   void SetOutputUserMute(bool mute_on) override;
   void SetInputNodeGain(uint64_t node_id, int32_t gain) override;
   void SetInputMute(bool mute_on) override;
   void SetActiveOutputNode(uint64_t node_id) override;
   void SetActiveInputNode(uint64_t node_id) override;
   void AddActiveInputNode(uint64_t node_id) override;
   void RemoveActiveInputNode(uint64_t node_id) override;
   void AddActiveOutputNode(uint64_t node_id) override;
   void RemoveActiveOutputNode(uint64_t node_id) override;
   void SwapLeftRight(uint64_t node_id, bool swap) override;
+  void WaitForServiceToBeAvailable(
+      const WaitForServiceToBeAvailableCallback& callback) override;
 
   // Modifies an AudioNode from |node_list_| based on |audio_node.id|.
   // if the |audio_node.id| cannot be found in list, Add an
   // AudioNode to |node_list_|
   void InsertAudioNodeToList(const AudioNode& audio_node);
 
   // Removes an AudioNode from |node_list_| based on |node_id|.
   void RemoveAudioNodeFromList(const uint64_t& node_id);
 
   // Updates |node_list_| to contain |audio_nodes|.
@@ skipping 18 matching lines @@
   uint64_t active_input_node_id_;
   uint64_t active_output_node_id_;
   base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeCrasAudioClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_FAKE_CRAS_AUDIO_CLIENT_H_