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

ios/chrome/browser/ui/external_file_remover.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 IOS_CHROME_BROWSER_UI_EXTERNAL_FILE_REMOVER_H_
 #define IOS_CHROME_BROWSER_UI_EXTERNAL_FILE_REMOVER_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
@@ skipping 28 matching lines @@
   // Removes files received from other apps. If |all_files| is true, then
   // all files including files that may be referenced by tabs through restore
   // service or history. Otherwise, only the unreferenced files are removed.
   // |callback| is called when the removal finishes.
   void RemoveFiles(bool all_files, const base::Closure& callback);
   // Pointer to the tab restore service in the browser state associated with
   // |bvc_|.
   sessions::TabRestoreService* tabRestoreService_;
   // BrowserViewController used to get the referenced files. Must outlive this
   // object.
-  BrowserViewController* bvc_;
+  __unsafe_unretained BrowserViewController* bvc_;
   // Used to ensure |Remove()| is not run when this object is destroyed.
   base::WeakPtrFactory<ExternalFileRemover> weak_ptr_factory_;
   // Loads the |tabRestoreService_| if necessary. Removes all files received
   // from other apps if |all_files| is true. Otherwise, removes the unreferenced
   // files only. |callback| is called when the removal finishes.
   void Remove(bool all_files, const base::Closure& callback);
 };
 
 #endif  // IOS_CHROME_BROWSER_UI_EXTERNAL_FILE_REMOVER_H_