Use mojo SystemTray interfaces for both mash and classic ash

ash/common/system/tray/system_tray_notifier.h

 // Copyright 2016 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 ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_NOTIFIER_H_
 #define ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_NOTIFIER_H_
 
 #include <string>
 
 #include "ash/ash_export.h"
@@ skipping 47 matching lines @@
   // 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);
+  // TODO: Remove all these in favor of SystemTrayController.
+  //void AddClockObserver(ClockObserver* observer);
+  //void RemoveClockObserver(ClockObserver* observer);
   void NotifyRefreshClock();
-  void NotifyDateFormatChanged();
+  // void NotifyDateFormatChanged();
   void NotifySystemClockTimeUpdated();
   void NotifySystemClockCanSetTimeChanged(bool can_set_time);
 
   // Input methods.
   void AddIMEObserver(IMEObserver* observer);
   void RemoveIMEObserver(IMEObserver* observer);
   void NotifyRefreshIME();
   void NotifyRefreshIMEMenu(bool is_active);
 
   // Locale.
@@ skipping 111 matching lines @@
   base::ObserverList<TracingObserver> tracing_observers_;
   base::ObserverList<VirtualKeyboardObserver> virtual_keyboard_observers_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayNotifier);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_NOTIFIER_H_