[Night Light] CL2: Ash and system tray work

ash/system/tray/system_tray_item.h

 // Copyright (c) 2012 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_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 43 matching lines @@
     UMA_POWER = 16,
     UMA_ROTATION_LOCK = 17,
     UMA_SCREEN_CAPTURE = 18,
     UMA_SCREEN_SHARE = 19,
     UMA_SESSION_LENGTH_LIMIT = 20,
     UMA_SMS = 21,
     UMA_SUPERVISED_USER = 22,
     UMA_TRACING = 23,
     UMA_USER = 24,
     UMA_VPN = 25,
-    UMA_COUNT = 26,
+    UMA_NIGHT_LIGHT = 26,
+    UMA_COUNT = 27,
   };
 
   SystemTrayItem(SystemTray* system_tray, UmaType type);
   virtual ~SystemTrayItem();
 
   // Create* functions may return NULL if nothing should be displayed for the
   // type of view. The default implementations return NULL.
 
   // Returns a view to be displayed in the system tray. If this returns NULL,
   // then this item is not displayed in the tray.
@@ skipping 75 matching lines @@
 
   // Used to delay the transition to the detailed view.
   base::OneShotTimer transition_delay_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_