[ObjC ARC] Converts ios/chrome/browser/ui/history:history to ARC.

ios/chrome/browser/ui/history/history_service_facade.h

 // Copyright 2016 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 IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_SERVICE_FACADE_H_
 #define IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_SERVICE_FACADE_H_
 
 #include <memory>
 #include <string>
 
-#include "base/ios/weak_nsobject.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
 #include "base/strings/string16.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "base/timer/timer.h"
 #include "base/values.h"
 #include "components/history/core/browser/history_service_observer.h"
 #include "components/history/core/browser/url_row.h"
 #include "components/history/core/browser/web_history_service.h"
@@ skipping 136 matching lines @@
   base::OneShotTimer web_history_timer_;
 
   // Observer for HistoryService.
   ScopedObserver<history::HistoryService, history::HistoryServiceObserver>
       history_service_observer_;
 
   // The current browser state.
   ios::ChromeBrowserState* browser_state_;  // weak
 
   // Delegate for HistoryServiceFacade. Serves as client for HistoryService.
-  base::WeakNSProtocol<id<HistoryServiceFacadeDelegate>> delegate_;
+  __weak id<HistoryServiceFacadeDelegate> delegate_;
 
   base::WeakPtrFactory<HistoryServiceFacade> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryServiceFacade);
 };
 
 #endif  // IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_SERVICE_FACADE_H_