Remove unused linked_ptr inclusion

chrome/browser/safe_browsing/threat_details_history.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_SAFE_BROWSING_THREAT_DETAILS_HISTORY_H_
 #define CHROME_BROWSER_SAFE_BROWSING_THREAT_DETAILS_HISTORY_H_
 
 // This class gets redirect chain for urls from the history service.
 
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
-#include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "components/history/core/browser/history_service.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "net/base/completion_callback.h"
 
 class Profile;
@@ skipping 61 matching lines @@
   std::vector<RedirectChain> redirects_urls_;
 
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreatDetailsRedirectsCollector);
 };
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_THREAT_DETAILS_HISTORY_H_