Revert of "Implement the inert attribute"

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

 /*
  * Copyright (C) 2014, Google 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 36 matching lines @@
 class MODULES_EXPORT AXObjectCacheImpl : public AXObjectCacheBase {
   WTF_MAKE_NONCOPYABLE(AXObjectCacheImpl);
 
  public:
   static AXObjectCache* Create(Document&);
 
   explicit AXObjectCacheImpl(Document&);
   virtual ~AXObjectCacheImpl();
   DECLARE_VIRTUAL_TRACE();
 
-  Document& GetDocument() { return *document_; }
   AXObjectImpl* FocusedObject();
 
   void Dispose() override;
 
   void SelectionChanged(Node*) override;
   void ChildrenChanged(Node*) override;
   void ChildrenChanged(LayoutObject*) override;
   void CheckedStateChanged(Node*) override;
   virtual void ListboxOptionStateChanged(HTMLOptionElement*);
   virtual void ListboxSelectedChildrenChanged(HTMLSelectElement*);
@@ skipping 193 matching lines @@
 // This is the only subclass of AXObjectCache.
 DEFINE_TYPE_CASTS(AXObjectCacheImpl, AXObjectCache, cache, true, true);
 
 bool NodeHasRole(Node*, const String& role);
 // This will let you know if aria-hidden was explicitly set to false.
 bool IsNodeAriaVisible(Node*);
 
 }  // namespace blink
 
 #endif