Using ShellObserver instead of creating MaximizeModeController::Observer

ash/system/chromeos/power/tablet_power_button_controller.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_SYSTEM_CHROMEOS_POWER_TABLET_POWER_BUTTON_CONTROLLER_H_
 #define ASH_SYSTEM_CHROMEOS_POWER_TABLET_POWER_BUTTON_CONTROLLER_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
-#include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
+#include "ash/common/shell_observer.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/tick_clock.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chromeos/dbus/power_manager_client.h"
 #include "ui/events/devices/input_device_event_observer.h"
 #include "ui/events/event_handler.h"
 
 namespace ash {
 
 class LockStateController;
 
 // Handles power button events on convertible/tablet device. This class is
 // instantiated and used in PowerButtonController.
 class ASH_EXPORT TabletPowerButtonController
     : public chromeos::PowerManagerClient::Observer,
-      public MaximizeModeController::Observer,
+      public ShellObserver,
       public ui::EventHandler,
       public ui::InputDeviceEventObserver {
  public:
   // Helper class used by tablet power button tests to access internal state.
   class ASH_EXPORT TestApi {
    public:
     explicit TestApi(TabletPowerButtonController* controller);
     ~TestApi();
 
     // Returns true when |shutdown_timer_| is running.
@@ skipping 16 matching lines @@
   bool ShouldHandlePowerButtonEvents() const;
 
   // Handles a power button event.
   void OnPowerButtonEvent(bool down, const base::TimeTicks& timestamp);
 
   // Overridden from chromeos::PowerManagerClient::Observer:
   void PowerManagerRestarted() override;
   void BrightnessChanged(int level, bool user_initiated) override;
   void SuspendDone(const base::TimeDelta& sleep_duration) override;
 
-  // Overridden from MaximizeModeController::Observer:
-  void OnEnterMaximizeMode() override;
-  void OnLeaveMaximizeMode() override;
+  // Overridden from ShellObserver:
+  void OnMaximizeModeStarted() override;
+  void OnMaximizeModeEnded() override;
 
   // Overridden from ui::EventHandler:
   void OnKeyEvent(ui::KeyEvent* event) override;
   void OnMouseEvent(ui::MouseEvent* event) override;
 
   // Overridden from ui::InputDeviceObserver:
   void OnStylusStateChanged(ui::StylusState state) override;
 
   // Overrides the tick clock used by |this| for testing.
   void SetTickClockForTesting(std::unique_ptr<base::TickClock> tick_clock);
@@ skipping 48 matching lines @@
   LockStateController* controller_;  // Not owned.
 
   base::WeakPtrFactory<TabletPowerButtonController> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TabletPowerButtonController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_POWER_TABLET_POWER_BUTTON_CONTROLLER_H_