Remove some linked_ptr c/b/extension

chrome/browser/extensions/extension_action_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_EXTENSIONS_EXTENSION_ACTION_MANAGER_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_ACTION_MANAGER_H_
 
 #include <map>
+#include <memory>
 #include <string>
 
 #include "base/scoped_observer.h"
 #include "chrome/common/extensions/api/extension_action/action_info.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "extensions/browser/extension_registry_observer.h"
 
 class ExtensionAction;
 class Profile;
 
@@ skipping 45 matching lines @@
   Profile* profile_;
 
   // Listen to extension unloaded notifications.
   ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
       extension_registry_observer_;
 
   // Keyed by Extension ID.  These maps are populated lazily when their
   // ExtensionAction is first requested, and the entries are removed when the
   // extension is unloaded.  Not every extension has a page action or browser
   // action.
-  typedef std::map<std::string, linked_ptr<ExtensionAction> > ExtIdToActionMap;
+  using ExtIdToActionMap =
+      std::map<std::string, std::unique_ptr<ExtensionAction>>;
   mutable ExtIdToActionMap page_actions_;
   mutable ExtIdToActionMap browser_actions_;
   mutable ExtIdToActionMap system_indicators_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_ACTION_MANAGER_H_