Deprecate NonThreadSafe in components/sync in favor of SequenceChecker.

components/sync/engine/attachments/fake_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_FAKE_ATTACHMENT_UPLOADER_H_
 #define COMPONENTS_SYNC_ENGINE_ATTACHMENTS_FAKE_ATTACHMENT_UPLOADER_H_
 
 #include "base/macros.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/sequence_checker.h"
 #include "components/sync/engine/attachments/attachment_uploader.h"
 
 namespace syncer {
 
 // A fake implementation of AttachmentUploader.
-class FakeAttachmentUploader : public AttachmentUploader,
-                               public base::NonThreadSafe {
+class FakeAttachmentUploader : public AttachmentUploader {
  public:
   FakeAttachmentUploader();
   ~FakeAttachmentUploader() override;
 
   // AttachmentUploader implementation.
   void UploadAttachment(const Attachment& attachment,
                         const UploadCallback& callback) override;
 
  private:
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(FakeAttachmentUploader);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_ATTACHMENTS_FAKE_ATTACHMENT_UPLOADER_H_