Revert of Refactor backdrop

components/exo/wm_helper.h

Index: components/exo/wm_helper.h
diff --git a/components/exo/wm_helper.h b/components/exo/wm_helper.h
index 84245f6b7abbed25dc173e0d9b02ab6443df4080..ad0aeb6ac5a49c4ade7b17c4aac25ecff5873d22 100644
--- a/components/exo/wm_helper.h
+++ b/components/exo/wm_helper.h
@@ -63,6 +63,14 @@
     virtual ~MaximizeModeObserver() {}
   };
 
+  class AccessibilityObserver {
+   public:
+    virtual void OnAccessibilityModeChanged() = 0;
+
+   protected:
+    virtual ~AccessibilityObserver() {}
+  };
+
   class InputDeviceEventObserver {
    public:
     virtual void OnKeyboardDeviceConfigurationChanged() = 0;
@@ -92,6 +100,8 @@
   void RemoveCursorObserver(CursorObserver* observer);
   void AddMaximizeModeObserver(MaximizeModeObserver* observer);
   void RemoveMaximizeModeObserver(MaximizeModeObserver* observer);
+  void AddAccessibilityObserver(AccessibilityObserver* observer);
+  void RemoveAccessibilityObserver(AccessibilityObserver* observer);
   void AddInputDeviceEventObserver(InputDeviceEventObserver* observer);
   void RemoveInputDeviceEventObserver(InputDeviceEventObserver* observer);
   void AddDisplayConfigurationObserver(DisplayConfigurationObserver* observer);
@@ -110,6 +120,8 @@
   virtual void AddPostTargetHandler(ui::EventHandler* handler) = 0;
   virtual void RemovePostTargetHandler(ui::EventHandler* handler) = 0;
   virtual bool IsMaximizeModeWindowManagerEnabled() const = 0;
+  virtual bool IsSpokenFeedbackEnabled() const = 0;
+  virtual void PlayEarcon(int sound_key) const = 0;
 
  protected:
   WMHelper();
@@ -123,6 +135,7 @@
   void NotifyMaximizeModeStarted();
   void NotifyMaximizeModeEnding();
   void NotifyMaximizeModeEnded();
+  void NotifyAccessibilityModeChanged();
   void NotifyKeyboardDeviceConfigurationChanged();
   void NotifyDisplayConfigurationChanged();
 
@@ -131,6 +144,7 @@
   base::ObserverList<FocusObserver> focus_observers_;
   base::ObserverList<CursorObserver> cursor_observers_;
   base::ObserverList<MaximizeModeObserver> maximize_mode_observers_;
+  base::ObserverList<AccessibilityObserver> accessibility_observers_;
   base::ObserverList<InputDeviceEventObserver> input_device_event_observers_;
   base::ObserverList<DisplayConfigurationObserver> display_config_observers_;