Reland of Uses the activedescendant_changed event received from Blink to fire the right focus event

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

 /*
  * Copyright (C) 2008 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
@@ skipping 29 matching lines @@
 
 private:
     AXListBox(LayoutObject*, AXObjectCacheImpl&);
 
 public:
     static AXListBox* create(LayoutObject*, AXObjectCacheImpl&);
     ~AXListBox() override;
 
     AccessibilityRole determineAccessibilityRole() final;
     bool isAXListBox() const override { return true; }
-    AXObject* activeDescendant() const override;
+    AXObject* activeDescendant() final;
 
     void activeIndexChanged();
 
 private:
     int m_activeIndex;
 };
 
 DEFINE_AX_OBJECT_TYPE_CASTS(AXListBox, isAXListBox());
 
 } // namespace blink
 
 #endif // AXListBox_h