exo: Use WMHelper to access ash accessibility related features.

components/exo/wm_helper_mus.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_MUS_H_
 #define COMPONENTS_EXO_WM_HELPER_MUS_H_
 
 #include "base/macros.h"
 #include "components/exo/wm_helper.h"
 #include "services/ui/public/cpp/window_tree_client_observer.h"
@@ skipping 15 matching lines @@
   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;
 
   // Overriden from ui::WindowTreeClientObserver:
   void OnWindowTreeFocusChanged(ui::Window* gained_focus,
                                 ui::Window* lost_focus) override;
 
   // Overriden from ui::client::FocusChangeObserver:
   void OnWindowFocused(aura::Window* gained_focus,
                        aura::Window* lost_focus) override;
 
  private:
   aura::Window* active_window_;
   aura::Window* focused_window_;
 
   DISALLOW_COPY_AND_ASSIGN(WMHelperMus);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_WM_HELPER_H_