Sync volume state using cras signal OutputNodeVolumeChanged.

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 42 matching lines @@
   // Removes an AudioNode from |node_list_| based on |node_id|.
   void RemoveAudioNodeFromList(const uint64_t& node_id);
 
   // Updates |node_list_| to contain |audio_nodes|.
   void SetAudioNodesForTesting(const AudioNodeList& audio_nodes);
 
   // Calls SetAudioNodesForTesting() and additionally notifies |observers_|.
   void SetAudioNodesAndNotifyObserversForTesting(
       const AudioNodeList& new_nodes);
 
+  // Generates fake signal for OutputNodeVolumeChanged.
+  void NotifyOutputNodeVolumeChangedForTesting(uint64_t node_id, int volume);
+
   const AudioNodeList& node_list() const { return node_list_; }
   const uint64_t& active_input_node_id() const { return active_input_node_id_; }
   const uint64_t& active_output_node_id() const {
     return active_output_node_id_;
   }
+  void set_notify_volume_change_with_delay(bool notify_with_delay) {
+    notify_volume_change_with_delay_ = notify_with_delay;
+  }
 
  private:
-  // Find a node in the list based on the id.
+  // Finds a node in the list based on the id.
   AudioNodeList::iterator FindNode(uint64_t node_id);
 
   VolumeState volume_state_;
   AudioNodeList node_list_;
   uint64_t active_input_node_id_;
   uint64_t active_output_node_id_;
+  // By default, immediately sends OutputNodeVolumeChange signal following the
+  // SetOutputNodeVolume fake dbus call.
+  bool notify_volume_change_with_delay_ = false;
   base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeCrasAudioClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_FAKE_CRAS_AUDIO_CLIENT_H_