Using ShellObserver instead of creating MaximizeModeController::Observer

ash/system/chromeos/power/tablet_power_button_controller.cc

 // 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.
 
 #include "ash/system/chromeos/power/tablet_power_button_controller.h"
 
 #include "ash/common/accessibility_delegate.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shell_delegate.h"
+#include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/shell.h"
 #include "ash/wm/lock_state_controller.h"
 #include "base/time/default_tick_clock.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "ui/events/devices/input_device_manager.h"
 #include "ui/events/devices/stylus_state.h"
 #include "ui/events/event.h"
 
 namespace ash {
@@ skipping 45 matching lines @@
 
 TabletPowerButtonController::TabletPowerButtonController(
     LockStateController* controller)
     : tick_clock_(new base::DefaultTickClock()),
       last_resume_time_(base::TimeTicks()),
       force_off_on_button_up_(true),
       controller_(controller),
       weak_ptr_factory_(this) {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(
       this);
-  if (WmShell::Get()->maximize_mode_controller())
-    WmShell::Get()->maximize_mode_controller()->AddObserver(this);
+  WmShell::Get()->AddShellObserver(this);
   ui::InputDeviceManager::GetInstance()->AddObserver(this);
   Shell::GetInstance()->PrependPreTargetHandler(this);
 
   GetInitialBacklightsForcedOff();
 }
 
 TabletPowerButtonController::~TabletPowerButtonController() {
   Shell::GetInstance()->RemovePreTargetHandler(this);
   ui::InputDeviceManager::GetInstance()->RemoveObserver(this);
-  if (WmShell::Get()->maximize_mode_controller())
-    WmShell::Get()->maximize_mode_controller()->RemoveObserver(this);
+  WmShell::Get()->RemoveShellObserver(this);
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->RemoveObserver(
       this);
 }
 
 bool TabletPowerButtonController::ShouldHandlePowerButtonEvents() const {
   return IsTabletModeSupported();
 }
 
 void TabletPowerButtonController::OnPowerButtonEvent(
     bool down,
@@ skipping 37 matching lines @@
 void TabletPowerButtonController::BrightnessChanged(int level,
                                                     bool user_initiated) {
   brightness_level_is_zero_ = level == 0;
 }
 
 void TabletPowerButtonController::SuspendDone(
     const base::TimeDelta& sleep_duration) {
   last_resume_time_ = tick_clock_->NowTicks();
 }
 
-void TabletPowerButtonController::OnEnterMaximizeMode() {
+void TabletPowerButtonController::OnMaximizeModeStarted() {
   shutdown_timer_.Stop();
   if (controller_->CanCancelShutdownAnimation())
     controller_->CancelShutdownAnimation();
 }
 
-void TabletPowerButtonController::OnLeaveMaximizeMode() {
+void TabletPowerButtonController::OnMaximizeModeEnded() {
   shutdown_timer_.Stop();
   if (controller_->CanCancelShutdownAnimation())
     controller_->CancelShutdownAnimation();
 }
 
 void TabletPowerButtonController::OnKeyEvent(ui::KeyEvent* event) {
   // Ignore key events generated by the power button since power button activity
   // is already handled by OnPowerButtonEvent().
   if (event->key_code() == ui::VKEY_POWER)
     return;
@@ skipping 75 matching lines @@
       WmShell::Get()->GetSessionStateDelegate();
   if (session_state_delegate->ShouldLockScreenAutomatically() &&
       session_state_delegate->CanLockScreen() &&
       !session_state_delegate->IsUserSessionBlocked() &&
       !controller_->LockRequested()) {
     session_state_delegate->LockScreen();
   }
 }
 
 }  // namespace ash