Deprecate NonThreadSafe in components/sync in favor of SequenceChecker.

components/sync/engine/attachments/fake_attachment_uploader.cc

Index: components/sync/engine/attachments/fake_attachment_uploader.cc
diff --git a/components/sync/engine/attachments/fake_attachment_uploader.cc b/components/sync/engine/attachments/fake_attachment_uploader.cc
index 3560e733286828dca8f1782e7550066b86dfac00..f5f7ad591951d2b777e016f70ac071ebf927b384 100644
--- a/components/sync/engine/attachments/fake_attachment_uploader.cc
+++ b/components/sync/engine/attachments/fake_attachment_uploader.cc
@@ -14,16 +14,16 @@
 namespace syncer {
 
 FakeAttachmentUploader::FakeAttachmentUploader() {
-  DCHECK(CalledOnValidThread());
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 }
 
 FakeAttachmentUploader::~FakeAttachmentUploader() {
-  DCHECK(CalledOnValidThread());
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 }
 
 void FakeAttachmentUploader::UploadAttachment(const Attachment& attachment,
                                               const UploadCallback& callback) {
-  DCHECK(CalledOnValidThread());
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!attachment.GetId().GetProto().unique_id().empty());
 
   UploadResult result = UPLOAD_SUCCESS;