Get rid of extraneous accessibility tree traversal code.

Source/core/accessibility/AccessibilityNodeObject.cpp

 /*
 * Copyright (C) 2012, 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 1261 matching lines @@
         return 0;
 
     Node* firstChild = node()->firstChild();
 
     if (!firstChild)
         return 0;
 
     return axObjectCache()->getOrCreate(firstChild);
 }
 
-AccessibilityObject* AccessibilityNodeObject::lastChild() const
-{
-    if (!node())
-        return 0;
-
-    Node* lastChild = node()->lastChild();
-    if (!lastChild)
-        return 0;
-
-    return axObjectCache()->getOrCreate(lastChild);
-}
-
-AccessibilityObject* AccessibilityNodeObject::previousSibling() const
-{
-    if (!node())
-        return 0;
-
-    Node* previousSibling = node()->previousSibling();
-    if (!previousSibling)
-        return 0;
-
-    return axObjectCache()->getOrCreate(previousSibling);
-}
-
 AccessibilityObject* AccessibilityNodeObject::nextSibling() const
 {
     if (!node())
         return 0;
 
     Node* nextSibling = node()->nextSibling();
     if (!nextSibling)
         return 0;
 
     return axObjectCache()->getOrCreate(nextSibling);
@@ skipping 389 matching lines @@
         useTextUnderElement = true;
 
     if (useTextUnderElement) {
         String text = textUnderElement();
         if (!text.isEmpty())
             textOrder.append(AccessibilityText(text, ChildrenText));
     }
 }
 
 } // namespace WebCore