Converts WmActivationObserver to aura::client::ActivationChangeObserver

ash/aura/wm_shell_aura.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/aura/wm_shell_aura.h"
 
 #include <utility>
 
 #include "ash/aura/key_event_watcher_aura.h"
 #include "ash/aura/pointer_watcher_adapter.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shell_delegate.h"
 #include "ash/common/shell_observer.h"
 #include "ash/common/wm/maximize_mode/scoped_disable_internal_mouse_and_keyboard.h"
 #include "ash/common/wm/mru_window_tracker.h"
 #include "ash/common/wm/overview/window_selector_controller.h"
-#include "ash/common/wm_activation_observer.h"
 #include "ash/common/wm_display_observer.h"
 #include "ash/common/wm_window.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/host/ash_window_tree_host_init_params.h"
 #include "ash/laser/laser_pointer_controller.h"
 #include "ash/magnifier/partial_magnification_controller.h"
 #include "ash/metrics/task_switch_metrics_recorder.h"
 #include "ash/shared/immersive_fullscreen_controller.h"
 #include "ash/shell.h"
 #include "ash/touch/touch_uma.h"
@@ skipping 278 matching lines @@
   for (auto& observer : display_observers_)
     observer.OnDisplayConfigurationChanging();
 }
 
 void WmShellAura::OnDisplayConfigurationChanged() {
   for (auto& observer : display_observers_)
     observer.OnDisplayConfigurationChanged();
 }
 
 }  // namespace ash