Remove code that is unused after ContextMenu cleanup

Source/core/history/BackForwardController.cpp

 /*
  * 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 30 matching lines @@
 
 BackForwardController::~BackForwardController()
 {
 }
 
 PassOwnPtr<BackForwardController> BackForwardController::create(Page* page, BackForwardClient* client)
 {
     return adoptPtr(new BackForwardController(page, client));
 }
 
-bool BackForwardController::canGoBackOrForward(int distance) const
-{
-    return m_page->canGoBackOrForward(distance);
-}
-
 void BackForwardController::goBackOrForward(int distance)
 {
     m_page->goBackOrForward(distance);
 }
 
 bool BackForwardController::goBack()
 {
     return m_page->goBack();
 }
 
@@ skipping 36 matching lines @@
 {
     return m_client->isActive();
 }
 
 void BackForwardController::close()
 {
     m_client->close();
 }
 
 } // namespace WebCore