Add user action for changing the active window in Ash overview mode

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/session/session_state_delegate.h"
 #include "ash/shelf/shelf_delegate.h"
 #include "ash/shelf/shelf_item_types.h"
 #include "ash/shelf/shelf_layout_manager.h"
@@ skipping 559 matching lines @@
     case ash::UMA_WINDOW_MAXIMIZE_BUTTON_MAXIMIZE_LEFT:
       base::RecordAction(base::UserMetricsAction("MaxButton_MaxLeft"));
       break;
     case ash::UMA_WINDOW_MAXIMIZE_BUTTON_MAXIMIZE_RIGHT:
       base::RecordAction(base::UserMetricsAction("MaxButton_MaxRight"));
       break;
     case ash::UMA_WINDOW_OVERVIEW:
       base::RecordAction(
           base::UserMetricsAction("WindowSelector_Overview"));
       break;
+    case ash::UMA_WINDOW_OVERVIEW_ACTIVE_WINDOW_CHANGED:
+      base::RecordAction(
+          base::UserMetricsAction("WindowSelector_ActiveWindowChanged"));
+      break;
     case ash::UMA_WINDOW_OVERVIEW_ENTER_KEY:
       base::RecordAction(
           base::UserMetricsAction("WindowSelector_OverviewEnterKey"));
       break;
     case ash::UMA_WINDOW_CYCLE:
       base::RecordAction(
           base::UserMetricsAction("WindowCycleController_Cycle"));
       break;
   }
 }
@@ skipping 33 matching lines @@
   return IsUserActive() && !IsKioskModeActive();
 }
 
 void UserMetricsRecorder::StartTimer() {
   timer_.Start(FROM_HERE,
                base::TimeDelta::FromSeconds(kAshPeriodicMetricsTimeInSeconds),
                this, &UserMetricsRecorder::RecordPeriodicMetrics);
 }
 
 }  // namespace ash