Added UMA statistics for changing the active window via click or touch events.

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/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"
 #include "ash/shelf/shelf_model.h"
 #include "ash/shelf/shelf_view.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/tray/system_tray_delegate.h"
@@ skipping 212 matching lines @@
       base::RecordAction(
           base::UserMetricsAction("Accel_Restart_PowerButton"));
       break;
     case ash::UMA_ACCEL_SHUT_DOWN_POWER_BUTTON:
       base::RecordAction(
           base::UserMetricsAction("Accel_ShutDown_PowerButton"));
       break;
     case ash::UMA_CLOSE_THROUGH_CONTEXT_MENU:
       base::RecordAction(base::UserMetricsAction("CloseFromContextMenu"));
       break;
+    case ash::UMA_DESKTOP_SWITCH_TASK:
+      base::RecordAction(base::UserMetricsAction("Desktop_SwitchTask"));
+      task_switch_metrics_recorder_.OnTaskSwitch(
+          TaskSwitchMetricsRecorder::kDesktop);
+      break;
     case ash::UMA_DRAG_MAXIMIZE_LEFT:
       base::RecordAction(base::UserMetricsAction("WindowDrag_MaximizeLeft"));
       break;
     case ash::UMA_DRAG_MAXIMIZE_RIGHT:
       base::RecordAction(base::UserMetricsAction("WindowDrag_MaximizeRight"));
       break;
     case ash::UMA_GESTURE_OVERVIEW:
       base::RecordAction(base::UserMetricsAction("Gesture_Overview"));
       break;
     case ash::UMA_LAUNCHER_BUTTON_PRESSED_WITH_MOUSE:
@@ skipping 342 matching lines @@
       base::RecordAction(
           base::UserMetricsAction("WindowSelector_OverviewEnterKey"));
       break;
     case ash::UMA_WINDOW_CYCLE:
       base::RecordAction(
           base::UserMetricsAction("WindowCycleController_Cycle"));
       break;
   }
 }
 
+void UserMetricsRecorder::OnShellInitialized() {
+  if (!desktop_task_switch_metric_recorder_) {

[sky, 2015/06/04 20:10:52]

Please add comment as to why the conditional.

[bruthig, 2015/06/05 17:28:21]

Done.

+    desktop_task_switch_metric_recorder_.reset(
+        new DesktopTaskSwitchMetricRecorder());
+  }
+}
+
+void UserMetricsRecorder::OnShellShuttingDown() {
+  if (desktop_task_switch_metric_recorder_)

[sky, 2015/06/04 20:10:52]

Conditional is not needed.

[bruthig, 2015/06/05 17:28:21]

Done.

+    desktop_task_switch_metric_recorder_.reset();
+}
+
 void UserMetricsRecorder::RecordPeriodicMetrics() {
   ShelfLayoutManager* manager =
       ShelfLayoutManager::ForShelf(Shell::GetPrimaryRootWindow());
   // TODO(bruthig): Investigating whether the check for |manager| is necessary
   // and add tests if it is.
   if (manager) {
     // TODO(bruthig): Consider tracking the time spent in each alignment.
     UMA_HISTOGRAM_ENUMERATION("Ash.ShelfAlignmentOverTime",
                               manager->SelectValueForShelfAlignment(
                                   SHELF_ALIGNMENT_UMA_ENUM_VALUE_BOTTOM,
@@ skipping 22 matching lines @@
   return IsUserActive() && !IsKioskModeActive();
 }
 
 void UserMetricsRecorder::StartTimer() {
   timer_.Start(FROM_HERE,
                base::TimeDelta::FromSeconds(kAshPeriodicMetricsTimeInSeconds),
                this, &UserMetricsRecorder::RecordPeriodicMetrics);
 }
 
 }  // namespace ash