Convert //chrome/browser/sync_file_system from scoped_ptr to std::unique_ptr

chrome/browser/sync_file_system/drive_backend/callback_tracker.h

 // Copyright 2014 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_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_TRACKER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_TRACKER_H_
 
 #include <map>
 
 #include "base/bind.h"
@@ skipping 41 matching lines @@
     helpers_[helper] = abort_closure;
     return base::Bind(&internal::InvokeAndInvalidateHelper<T>::Run,
                       helper->AsWeakPtr(), callback);
   }
 
   void AbortAll();
 
  private:
   friend class internal::AbortHelper;
 
-  scoped_ptr<internal::AbortHelper> PassAbortHelper(
+  std::unique_ptr<internal::AbortHelper> PassAbortHelper(
       internal::AbortHelper* helper);
 
   AbortClosureByHelper helpers_;  // Owns AbortHelpers.
 
   DISALLOW_COPY_AND_ASSIGN(CallbackTracker);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_TRACKER_H_