[Night Light] CL2: Ash and system tray work

ash/metrics/user_metrics_recorder.cc

 // Copyright 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.
 
 #include "ash/metrics/user_metrics_recorder.h"
 
 #include "ash/metrics/desktop_task_switch_metric_recorder.h"
 #include "ash/metrics/pointer_metrics_recorder.h"
 #include "ash/public/cpp/shelf_item.h"
 #include "ash/public/cpp/shell_window_ids.h"
@@ skipping 529 matching lines @@
       break;
     case UMA_TOUCHSCREEN_TAP_DOWN:
       RecordAction(UserMetricsAction("Touchscreen_Down"));
       break;
     case UMA_TRAY_HELP:
       RecordAction(UserMetricsAction("Tray_Help"));
       break;
     case UMA_TRAY_LOCK_SCREEN:
       RecordAction(UserMetricsAction("Tray_LockScreen"));
       break;
+    case UMA_TRAY_NIGHT_LIGHT:
+      RecordAction(UserMetricsAction("Tray_NightLight"));
+      break;
     case UMA_TRAY_OVERVIEW:
       RecordAction(UserMetricsAction("Tray_Overview"));
       break;
     case UMA_TRAY_SETTINGS:
       RecordAction(UserMetricsAction("Tray_Settings"));
       break;
     case UMA_TRAY_SHUT_DOWN:
       RecordAction(UserMetricsAction("Tray_ShutDown"));
       break;
     case UMA_WINDOW_APP_CLOSE_BUTTON_CLICK:
@@ skipping 95 matching lines @@
   return IsUserActive() && !IsKioskModeActive() && !IsArcKioskModeActive();
 }
 
 void UserMetricsRecorder::StartTimer() {
   timer_.Start(FROM_HERE,
                base::TimeDelta::FromSeconds(kAshPeriodicMetricsTimeInSeconds),
                this, &UserMetricsRecorder::RecordPeriodicMetrics);
 }
 
 }  // namespace ash