Refactor backdrop that is currently used in the maximized mode.

components/exo/wm_helper_ash.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 COMPONENTS_EXO_WM_HELPER_ASH_H_
 #define COMPONENTS_EXO_WM_HELPER_ASH_H_
 
 #include "ash/shell_observer.h"
-#include "ash/system/accessibility_observer.h"
 #include "ash/wm_display_observer.h"
 #include "base/macros.h"
 #include "components/exo/wm_helper.h"
 #include "ui/aura/client/cursor_client_observer.h"
 #include "ui/aura/client/focus_change_observer.h"
 #include "ui/events/devices/input_device_event_observer.h"
 #include "ui/wm/public/activation_change_observer.h"
 
 namespace exo {
 
 // A helper class for accessing WindowManager related features.
 class WMHelperAsh : public WMHelper,
                     public aura::client::ActivationChangeObserver,
                     public aura::client::FocusChangeObserver,
                     public aura::client::CursorClientObserver,
-                    public ash::AccessibilityObserver,
                     public ash::ShellObserver,
                     public ash::WmDisplayObserver,
                     public ui::InputDeviceEventObserver {
  public:
   WMHelperAsh();
   ~WMHelperAsh() override;
 
   // Overridden from WMHelper:
   const display::ManagedDisplayInfo GetDisplayInfo(
       int64_t display_id) const override;
   aura::Window* GetContainer(int container_id) override;
   aura::Window* GetActiveWindow() const override;
   aura::Window* GetFocusedWindow() const override;
   ui::CursorSetType GetCursorSet() const override;
   void AddPreTargetHandler(ui::EventHandler* handler) override;
   void PrependPreTargetHandler(ui::EventHandler* handler) override;
   void RemovePreTargetHandler(ui::EventHandler* handler) override;
   void AddPostTargetHandler(ui::EventHandler* handler) override;
   void RemovePostTargetHandler(ui::EventHandler* handler) override;
   bool IsMaximizeModeWindowManagerEnabled() const override;
-  bool IsSpokenFeedbackEnabled() const override;
-  void PlayEarcon(int sound_key) const override;
 
   // Overridden from aura::client::ActivationChangeObserver:
   void OnWindowActivated(
       aura::client::ActivationChangeObserver::ActivationReason reason,
       aura::Window* gained_active,
       aura::Window* lost_active) override;
 
   // Overridden from aura::client::FocusChangeObserver:
   void OnWindowFocused(aura::Window* gained_focus,
                        aura::Window* lost_focus) override;
 
   // Overridden from aura::client::CursorClientObserver:
   void OnCursorVisibilityChanged(bool is_visible) override;
   void OnCursorSetChanged(ui::CursorSetType cursor_set) override;
 
-  // Overridden from ash::AccessibilityObserver:
-  void OnAccessibilityModeChanged(
-      ash::AccessibilityNotificationVisibility notify) override;
-
   // Overridden from ash::ShellObserver:
   void OnMaximizeModeStarted() override;
   void OnMaximizeModeEnding() override;
   void OnMaximizeModeEnded() override;
 
   // Overridden from ash::WmDisplayObserver:
   void OnDisplayConfigurationChanged() override;
 
   // Overridden from ui::InputDeviceEventObserver:
   void OnKeyboardDeviceConfigurationChanged() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WMHelperAsh);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_WM_HELPER_H_