Remove BackForwardClient, cleanup starting a history navigation

Source/core/loader/NavigationScheduler.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2009 Adam Barth. 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
@@ skipping 63 matching lines @@
     explicit NavigationScheduler(LocalFrame*);
     ~NavigationScheduler();
 
     bool locationChangePending();
 
     void scheduleRedirect(double delay, const String& url);
     void scheduleLocationChange(Document*, const String& url, bool lockBackForwardList = true);
     void schedulePageBlock(Document*);
     void scheduleFormSubmission(PassRefPtrWillBeRawPtr<FormSubmission>);
     void scheduleReload();
-    void scheduleHistoryNavigation(int steps);
 
     void startTimer();
     void cancel();
 
     void trace(Visitor*);
 
 private:
     bool shouldScheduleNavigation() const;
     bool shouldScheduleNavigation(const String& url) const;
 
     void timerFired(Timer<NavigationScheduler>*);
     void schedule(PassOwnPtr<ScheduledNavigation>);
 
     static bool mustLockBackForwardList(LocalFrame* targetFrame);
 
     RawPtrWillBeMember<LocalFrame> m_frame;
     Timer<NavigationScheduler> m_timer;
     OwnPtr<ScheduledNavigation> m_redirect;
 };
 
 } // namespace blink
 
 #endif // NavigationScheduler_h