Revert of Refactor backdrop

components/exo/wm_helper_ash.h

Index: components/exo/wm_helper_ash.h
diff --git a/components/exo/wm_helper_ash.h b/components/exo/wm_helper_ash.h
index 21bde11eff85fcc9f3338fe806696d0bfd6cb73d..dc39a292e3b6827c307f62a6cb9955321d326e98 100644
--- a/components/exo/wm_helper_ash.h
+++ b/components/exo/wm_helper_ash.h
@@ -6,6 +6,7 @@
 #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"
@@ -21,6 +22,7 @@
                     public aura::client::ActivationChangeObserver,
                     public aura::client::FocusChangeObserver,
                     public aura::client::CursorClientObserver,
+                    public ash::AccessibilityObserver,
                     public ash::ShellObserver,
                     public ash::WmDisplayObserver,
                     public ui::InputDeviceEventObserver {
@@ -41,6 +43,8 @@
   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(
@@ -55,6 +59,10 @@
   // 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;