[Sync] Replace typedef with using.

components/sync/driver/sync_stopped_reporter.h

 // Copyright 2015 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 COMPONENTS_SYNC_DRIVER_SYNC_STOPPED_REPORTER_H_
 #define COMPONENTS_SYNC_DRIVER_SYNC_STOPPED_REPORTER_H_
 
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "url/gurl.h"
 
 namespace syncer {
 
 // Manages informing the sync server that sync has been disabled.
 // An implementation of URLFetcherDelegate was needed in order to
 // clean up the fetcher_ pointer when the request completes.
 class SyncStoppedReporter : public net::URLFetcherDelegate {
  public:
   enum Result { RESULT_SUCCESS, RESULT_ERROR, RESULT_TIMEOUT };
 
-  typedef base::Callback<void(const Result&)> ResultCallback;
+  using ResultCallback = base::Callback<void(const Result&)>;
 
   SyncStoppedReporter(
       const GURL& sync_service_url,
       const std::string& user_agent,
       const scoped_refptr<net::URLRequestContextGetter>& request_context,
       const ResultCallback& callback);
   ~SyncStoppedReporter() override;
 
   // Inform the sync server that sync was stopped on this device.
   // |access_token|, |cache_guid|, and |birthday| must not be empty.
@@ skipping 32 matching lines @@
 
   // A callback for request completion or timeout.
   ResultCallback callback_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncStoppedReporter);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_SYNC_STOPPED_REPORTER_H_