Moves MruWindowTracker into common

ash/wm/window_cycle_controller.cc

 // Copyright 2014 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/wm/window_cycle_controller.h"
 
+#include "ash/common/wm/mru_window_tracker.h"
 #include "ash/metrics/user_metrics_recorder.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
-#include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/window_cycle_list.h"
 #include "base/metrics/histogram.h"
 #include "ui/events/event.h"
 #include "ui/events/event_handler.h"
 
 namespace ash {
 
 namespace {
 
 // Returns the most recently active window from the |window_list| or nullptr
@@ skipping 100 matching lines @@
       active_window_before_window_cycle_ != active_window_after_window_cycle) {
     Shell::GetInstance()
         ->metrics()
         ->task_switch_metrics_recorder()
         .OnTaskSwitch(TaskSwitchMetricsRecorder::WINDOW_CYCLE_CONTROLLER);
   }
   active_window_before_window_cycle_ = nullptr;
 }
 
 }  // namespace ash