Implement the inert attribute

third_party/WebKit/Source/modules/accessibility/AXMenuListPopup.h

 /*
  * Copyright (C) 2010 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 31 matching lines @@
     return new AXMenuListPopup(ax_object_cache);
   }
 
   bool IsEnabled() const override;
   bool IsOffScreen() const override;
 
   void DidUpdateActiveOption(int option_index);
   void DidShow();
   void DidHide();
   AXObjectImpl* ActiveDescendant() final;
+  void UpdateChildrenIfNecessary() override;
 
  private:
   explicit AXMenuListPopup(AXObjectCacheImpl&);
 
   bool IsMenuListPopup() const override { return true; }
 
   AccessibilityRole RoleValue() const override { return kMenuListPopupRole; }
 
   bool IsVisible() const override;
   bool Press() override;
   void AddChildren() override;
-  void UpdateChildrenIfNecessary() override;
   bool ComputeAccessibilityIsIgnored(IgnoredReasons* = nullptr) const override;
 
   AXMenuListOption* MenuListOptionAXObject(HTMLElement*) const;
   int GetSelectedIndex() const;
 
   // Note that this may be -1 if nothing is selected.
   int active_index_;
 };
 
 DEFINE_AX_OBJECT_TYPE_CASTS(AXMenuListPopup, IsMenuListPopup());
 
 }  // namespace blink
 
 #endif  // AXMenuListPopup_h