Remove HistoryController::GetPreviousEntry.

content/renderer/history_controller.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /*
  * 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/)
  *
  * Redistribution and use in source and binary forms, with or without
@@ skipping 100 matching lines @@
 
   void GoToEntry(scoped_ptr<HistoryEntry> entry,
                  blink::WebURLRequest::CachePolicy cache_policy);
 
   void UpdateForCommit(RenderFrameImpl* frame,
                        const blink::WebHistoryItem& item,
                        blink::WebHistoryCommitType commit_type,
                        bool navigation_within_page);
 
   HistoryEntry* GetCurrentEntry();
-  HistoryEntry* GetPreviousEntry();
   blink::WebHistoryItem GetItemForNewChildFrame(RenderFrameImpl* frame) const;
   void RemoveChildrenForRedirect(RenderFrameImpl* frame);
 
  private:
   typedef std::vector<std::pair<blink::WebFrame*, blink::WebHistoryItem> >
       HistoryFrameLoadVector;
   void RecursiveGoToEntry(blink::WebFrame* frame,
                           HistoryFrameLoadVector& sameDocumentLoads,
                           HistoryFrameLoadVector& differentDocumentLoads);
 
   void UpdateForInitialLoadInChildFrame(RenderFrameImpl* frame,
                                         const blink::WebHistoryItem& item);
   void CreateNewBackForwardItem(RenderFrameImpl* frame,
                                 const blink::WebHistoryItem& item,
                                 bool clone_children_of_target);
 
   RenderViewImpl* render_view_;
 
   scoped_ptr<HistoryEntry> current_entry_;
-  scoped_ptr<HistoryEntry> previous_entry_;
   scoped_ptr<HistoryEntry> provisional_entry_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryController);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_HISTORY_CONTROLLER_H_