Using ShellObserver instead of creating MaximizeModeController::Observer

ash/system/chromeos/power/tablet_power_button_controller_unittest.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 <memory>
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/session/session_state_delegate.h"
@@ skipping 397 matching lines @@
 // When user switches convertible device between laptop mode and tablet mode,
 // power button may be pressed and held, which may cause unwanted shutdown.
 TEST_F(TabletPowerButtonControllerTest,
        EnterOrLeaveMaximizeModeWhilePressingPowerButton) {
   Initialize(LoginStatus::USER);
   SetShouldLockScreenAutomatically(true);
   EXPECT_FALSE(GetLockedState());
 
   power_manager_client_->SendPowerButtonEvent(true, tick_clock_->NowTicks());
   EXPECT_TRUE(test_api_->ShutdownTimerIsRunning());
-  tablet_controller_->OnEnterMaximizeMode();
+  tablet_controller_->OnMaximizeModeStarted();
   EXPECT_FALSE(test_api_->ShutdownTimerIsRunning());
   tick_clock_->Advance(base::TimeDelta::FromMilliseconds(1500));
   power_manager_client_->SendPowerButtonEvent(false, tick_clock_->NowTicks());
   EXPECT_FALSE(GetLockedState());
   EXPECT_FALSE(GetBacklightsForcedOff());
 
   power_manager_client_->SendPowerButtonEvent(true, tick_clock_->NowTicks());
   test_api_->TriggerShutdownTimeout();
   EXPECT_TRUE(lock_state_test_api_->shutdown_timer_is_running());
-  tablet_controller_->OnEnterMaximizeMode();
+  tablet_controller_->OnMaximizeModeStarted();
   EXPECT_FALSE(lock_state_test_api_->shutdown_timer_is_running());
   tick_clock_->Advance(base::TimeDelta::FromMilliseconds(2500));
   power_manager_client_->SendPowerButtonEvent(false, tick_clock_->NowTicks());
   EXPECT_FALSE(GetLockedState());
   EXPECT_FALSE(GetBacklightsForcedOff());
 
   power_manager_client_->SendPowerButtonEvent(true, tick_clock_->NowTicks());
   EXPECT_TRUE(test_api_->ShutdownTimerIsRunning());
-  tablet_controller_->OnLeaveMaximizeMode();
+  tablet_controller_->OnMaximizeModeEnded();
   EXPECT_FALSE(test_api_->ShutdownTimerIsRunning());
   tick_clock_->Advance(base::TimeDelta::FromMilliseconds(3500));
   power_manager_client_->SendPowerButtonEvent(false, tick_clock_->NowTicks());
   EXPECT_FALSE(GetLockedState());
   EXPECT_FALSE(GetBacklightsForcedOff());
 
   power_manager_client_->SendPowerButtonEvent(true, tick_clock_->NowTicks());
   test_api_->TriggerShutdownTimeout();
   EXPECT_TRUE(lock_state_test_api_->shutdown_timer_is_running());
-  tablet_controller_->OnLeaveMaximizeMode();
+  tablet_controller_->OnMaximizeModeEnded();
   EXPECT_FALSE(lock_state_test_api_->shutdown_timer_is_running());
   tick_clock_->Advance(base::TimeDelta::FromMilliseconds(4500));
   power_manager_client_->SendPowerButtonEvent(false, tick_clock_->NowTicks());
   EXPECT_FALSE(GetLockedState());
   EXPECT_FALSE(GetBacklightsForcedOff());
 }
 
 }  // namespace test
 }  // namespace ash