Switch the history backend from using page ids to navigation entry unique ids.

components/history/core/browser/visit_tracker.h

 // Copyright (c) 2010 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.
 
 #ifndef COMPONENTS_HISTORY_CORE_BROWSER_VISIT_TRACKER_H__
 #define COMPONENTS_HISTORY_CORE_BROWSER_VISIT_TRACKER_H__
 
 #include <map>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "components/history/core/browser/history_types.h"
 
 namespace history {
 
 // Tracks history transitions between pages. The history backend uses this to
 // link up page transitions to form a chain of page visits, and to set the
 // transition type properly.
 //
 // This class is not thread safe.
 class VisitTracker {
  public:
   VisitTracker();
   ~VisitTracker();
 
   // Notifications -------------------------------------------------------------
 
   void AddVisit(ContextID context_id,
-                int32 page_id,
+                int nav_entry_id,
                 const GURL& url,
                 VisitID visit_id);
 
   // When a RenderProcessHost is destroyed, we want to clear out our saved
   // transitions/visit IDs for it.
   void ClearCachedDataForContextID(ContextID context_id);
 
   // Querying ------------------------------------------------------------------
 
   // Returns the visit ID for the transition given information about the visit
   // supplied by the renderer. We will return 0 if there is no appropriate
   // referring visit.
-  VisitID GetLastVisit(ContextID context_id, int32 page_id, const GURL& url);
+  VisitID GetLastVisit(ContextID context_id,
+                       int nav_entry_id,
+                       const GURL& url);
 
  private:
   struct Transition {
     GURL url;          // URL that the event happened to.
-    int32 page_id;     // ID generated by the render process host.
+    int nav_entry_id;  // ID of the navigation entry.
     VisitID visit_id;  // Visit ID generated by history.
   };
   typedef std::vector<Transition> TransitionList;
   typedef std::map<ContextID, TransitionList*> ContextList;
 
   // Expires oldish items in the given transition list. This keeps the list
   // size small by removing items that are unlikely to be needed, which is
   // important for GetReferrer which does brute-force searches of this list.
   void CleanupTransitionList(TransitionList* transitions);
 
   // Maps render view hosts to lists of recent transitions.
   ContextList contexts_;
 
   DISALLOW_COPY_AND_ASSIGN(VisitTracker);
 };
 
 }  // namespace history
 
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_VISIT_TRACKER_H__