chromeos: Combine TrayAudio and TrayAudioChromeOs classes

ash/common/system/tray/system_tray_notifier.h

Index: ash/common/system/tray/system_tray_notifier.h
diff --git a/ash/common/system/tray/system_tray_notifier.h b/ash/common/system/tray/system_tray_notifier.h
index 3051575d263e6ad61aa9dbb845a8df8cef38cd91..8b6e4ec63f3bf0ccf1036076087e4ef8745a2480 100644
--- a/ash/common/system/tray/system_tray_notifier.h
+++ b/ash/common/system/tray/system_tray_notifier.h
@@ -20,7 +20,6 @@
 namespace ash {
 
 class AccessibilityObserver;
-class AudioObserver;
 class ClockObserver;
 class IMEObserver;
 struct UpdateInfo;
@@ -28,6 +27,7 @@ class UpdateObserver;
 class UserObserver;
 
 #if defined(OS_CHROMEOS)
+class AudioObserver;
 class BluetoothObserver;
 class EnterpriseDomainObserver;
 class LastWindowClosedObserver;
@@ -54,15 +54,6 @@ class ASH_EXPORT SystemTrayNotifier {
   void NotifyAccessibilityModeChanged(
       AccessibilityNotificationVisibility notify);
 
-  // Audio.
-  void AddAudioObserver(AudioObserver* observer);
-  void RemoveAudioObserver(AudioObserver* observer);
-  void NotifyAudioOutputVolumeChanged(uint64_t node_id, double volume);
-  void NotifyAudioOutputMuteChanged(bool mute_on, bool system_adjust);
-  void NotifyAudioNodesChanged();
-  void NotifyAudioActiveOutputNodeChanged();
-  void NotifyAudioActiveInputNodeChanged();
-
   // Date and time.
   void AddClockObserver(ClockObserver* observer);
   void RemoveClockObserver(ClockObserver* observer);
@@ -89,6 +80,15 @@ class ASH_EXPORT SystemTrayNotifier {
   void NotifyUserAddedToSession();
 
 #if defined(OS_CHROMEOS)
+  // Audio.
+  void AddAudioObserver(AudioObserver* observer);
+  void RemoveAudioObserver(AudioObserver* observer);
+  void NotifyAudioOutputVolumeChanged(uint64_t node_id, double volume);
+  void NotifyAudioOutputMuteChanged(bool mute_on, bool system_adjust);
+  void NotifyAudioNodesChanged();
+  void NotifyAudioActiveOutputNodeChanged();
+  void NotifyAudioActiveInputNodeChanged();
+
   // Bluetooth.
   void AddBluetoothObserver(BluetoothObserver* observer);
   void RemoveBluetoothObserver(BluetoothObserver* observer);
@@ -161,13 +161,13 @@ class ASH_EXPORT SystemTrayNotifier {
 
  private:
   base::ObserverList<AccessibilityObserver> accessibility_observers_;
-  base::ObserverList<AudioObserver> audio_observers_;
   base::ObserverList<ClockObserver> clock_observers_;
   base::ObserverList<IMEObserver> ime_observers_;
   base::ObserverList<UpdateObserver> update_observers_;
   base::ObserverList<UserObserver> user_observers_;
 
 #if defined(OS_CHROMEOS)
+  base::ObserverList<AudioObserver> audio_observers_;
   base::ObserverList<BluetoothObserver> bluetooth_observers_;
   base::ObserverList<EnterpriseDomainObserver> enterprise_domain_observers_;
   base::ObserverList<LastWindowClosedObserver> last_window_closed_observers_;