Get rid of extraneous accessibility tree traversal code.

public/webpage/WebAccessibilityObject.h

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 74 matching lines @@
     // still valid (not detached). Note that calling this method
     // can cause other WebAccessibilityObjects to become invalid, too,
     // so always call isDetached if updateBackingStoreAndCheckValidity
     // has been called on any object, or if any other WebCore code has run.
     WEBKIT_EXPORT bool updateBackingStoreAndCheckValidity();
 
     WEBKIT_EXPORT WebString accessibilityDescription() const;
     WEBKIT_EXPORT unsigned childCount() const;
 
     WEBKIT_EXPORT WebAccessibilityObject childAt(unsigned) const;
-    WEBKIT_EXPORT WebAccessibilityObject firstChild() const;
-    WEBKIT_EXPORT WebAccessibilityObject focusedChild() const;
-    WEBKIT_EXPORT WebAccessibilityObject lastChild() const;
-    WEBKIT_EXPORT WebAccessibilityObject nextSibling() const;
     WEBKIT_EXPORT WebAccessibilityObject parentObject() const;
-    WEBKIT_EXPORT WebAccessibilityObject previousSibling() const;
 
     WEBKIT_EXPORT bool isAnchor() const;
     WEBKIT_EXPORT bool isAriaReadOnly() const;
     WEBKIT_EXPORT bool isButtonStateMixed() const;
     WEBKIT_EXPORT bool isChecked() const;
     WEBKIT_EXPORT bool isCollapsed() const;
     WEBKIT_EXPORT bool isControl() const;
     WEBKIT_EXPORT bool isEnabled() const;
     WEBKIT_EXPORT bool isFocused() const;
     WEBKIT_EXPORT bool isHovered() const;
@@ skipping 101 matching lines @@
     operator WTF::PassRefPtr<WebCore::AccessibilityObject>() const;
 #endif
 
 private:
     WebPrivatePtr<WebCore::AccessibilityObject> m_private;
 };
 
 } // namespace WebKit
 
 #endif