[Sync] Replace typedef with using.

components/sync/engine/attachments/attachment_uploader.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 COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_UPLOADER_H_
 #define COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_UPLOADER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 12 matching lines @@
 class AttachmentUploader {
  public:
   // The result of an UploadAttachment operation.
   enum UploadResult {
     UPLOAD_SUCCESS,            // No error, attachment was uploaded
                                // successfully.
     UPLOAD_TRANSIENT_ERROR,    // A transient error occurred, try again later.
     UPLOAD_UNSPECIFIED_ERROR,  // An unspecified error occurred.
   };
 
-  typedef base::Callback<void(const UploadResult&, const AttachmentId&)>
-      UploadCallback;
+  using UploadCallback =
+      base::Callback<void(const UploadResult&, const AttachmentId&)>;
 
   virtual ~AttachmentUploader();
 
   // Upload |attachment| and invoke |callback| when done.
   //
   // |callback| will be invoked when the operation has completed (successfully
   // or otherwise).
   //
   // |callback| will receive an UploadResult code and the AttachmentId of the
   // newly uploaded attachment.
@@ skipping 23 matching lines @@
       const OAuth2TokenService::ScopeSet scopes,
       const scoped_refptr<OAuth2TokenServiceRequest::TokenServiceProvider>&
           token_service_provider,
       const std::string& store_birthday,
       ModelType model_type);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_UPLOADER_H_