Deprecate NonThreadSafe in components/sync in favor of SequenceChecker.

components/sync/engine_impl/attachments/attachment_downloader_impl.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_IMPL_ATTACHMENTS_ATTACHMENT_DOWNLOADER_IMPL_H_
 #define COMPONENTS_SYNC_ENGINE_IMPL_ATTACHMENTS_ATTACHMENT_DOWNLOADER_IMPL_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/sequence_checker.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/engine/attachments/attachment_downloader.h"
 #include "google_apis/gaia/oauth2_token_service_request.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "url/gurl.h"
 
 namespace net {
 class HttpResponseHeaders;
 }  // namespace net
 
 namespace syncer {
 
 // An implementation of AttachmentDownloader.
 class AttachmentDownloaderImpl : public AttachmentDownloader,
                                  public OAuth2TokenService::Consumer,
-                                 public net::URLFetcherDelegate,
-                                 public base::NonThreadSafe {
+                                 public net::URLFetcherDelegate {
  public:
   // |sync_service_url| is the URL of the sync service.
   //
   // |url_request_context_getter| provides a URLRequestContext.
   //
   // |account_id| is the account id to use for downloads.
   //
   // |scopes| is the set of scopes to use for downloads.
   //
   // |token_service_provider| provides an OAuth2 token service.
@@ skipping 69 matching lines @@
   std::string raw_store_birthday_;
 
   StateMap state_map_;
   // |requests_waiting_for_access_token_| only keeps references to DownloadState
   // objects while access token request is pending. It doesn't control objects'
   // lifetime.
   StateList requests_waiting_for_access_token_;
 
   ModelType model_type_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(AttachmentDownloaderImpl);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_IMPL_ATTACHMENTS_ATTACHMENT_DOWNLOADER_IMPL_H_