[Night Light] CL2: Ash and system tray work

ash/metrics/user_metrics_action.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_METRICS_USER_METRICS_ACTION_H_
 #define ASH_METRICS_USER_METRICS_ACTION_H_
 
 namespace ash {
 
 // Ash-owned user metrics.
@@ skipping 106 matching lines @@
   UMA_STATUS_AREA_VPN_ADD_THIRD_PARTY_CLICKED,
   UMA_STATUS_AREA_VPN_DISCONNECT_CLICKED,
   UMA_STATUS_AREA_VPN_SETTINGS_OPENED,
   UMA_TOGGLE_MAXIMIZE_CAPTION_CLICK,
   UMA_TOGGLE_MAXIMIZE_CAPTION_GESTURE,
   UMA_TOGGLE_SINGLE_AXIS_MAXIMIZE_BORDER_CLICK,
   UMA_TOUCHPAD_GESTURE_OVERVIEW,
   UMA_TOUCHSCREEN_TAP_DOWN,
   UMA_TRAY_HELP,
   UMA_TRAY_LOCK_SCREEN,
+  UMA_TRAY_NIGHT_LIGHT,
   UMA_TRAY_OVERVIEW,
   UMA_TRAY_SETTINGS,
   UMA_TRAY_SHUT_DOWN,
   UMA_WINDOW_APP_CLOSE_BUTTON_CLICK,
   UMA_WINDOW_CLOSE_BUTTON_CLICK,
   UMA_WINDOW_MAXIMIZE_BUTTON_CLICK_EXIT_FULLSCREEN,
   UMA_WINDOW_MAXIMIZE_BUTTON_CLICK_MAXIMIZE,
   UMA_WINDOW_MAXIMIZE_BUTTON_CLICK_MINIMIZE,
   UMA_WINDOW_MAXIMIZE_BUTTON_CLICK_RESTORE,
   UMA_WINDOW_MAXIMIZE_BUTTON_MAXIMIZE_LEFT,
@@ skipping 16 matching lines @@
   // Closing a window in overview mode by clicking the 'X' button.
   UMA_WINDOW_OVERVIEW_CLOSE_BUTTON,
 
   // Closing a window in overview mode by pressing Ctrl+w shortcut.
   UMA_WINDOW_OVERVIEW_CLOSE_KEY,
 };
 
 }  // namespace ash
 
 #endif  // ASH_METRICS_USER_METRICS_ACTION_H_