[NoStatePrefetch] Cancel repeated prefetches with FINAL_STATUS_DUPLICATE

chrome/browser/prerender/prerender_manager.h

 // Copyright (c) 2012 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 CHROME_BROWSER_PRERENDER_PRERENDER_MANAGER_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
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   // Deletes old WebContents that have been replaced by prerendered ones.  This
   // is needed because they're replaced in a callback from the old WebContents,
   // so cannot immediately be deleted.
   void DeleteOldWebContents();
 
   // Get information associated with a possible prefetch of |url|.
   void GetPrefetchInformation(const GURL& url,
                               base::TimeDelta* prefetch_age,
                               Origin* origin);
 
+  // Called when a prefetch has been used. Prefetches avoid cache revalidation
+  // only once.
+  void OnPrefetchUsed(const GURL& url);
+
   // Cleans up old NavigationRecord's.
   void CleanUpOldNavigations(std::vector<NavigationRecord>* navigations,
                              base::TimeDelta max_age);
 
   // Arrange for the given WebContents to be deleted asap. Delete |deleter| as
   // well.
   void ScheduleDeleteOldWebContents(std::unique_ptr<content::WebContents> tab,
                                     OnCloseWebContentsDeleter* deleter);
 
   // Adds to the history list.
@@ skipping 87 matching lines @@
   std::vector<std::unique_ptr<PrerenderManagerObserver>> observers_;
 
   base::WeakPtrFactory<PrerenderManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrerenderManager);
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_MANAGER_H_