Task Scheduler API migration: change BrowserThreadModelWorker to SequencedModelWorker

components/sync/engine/sequenced_model_worker.cc

Index: components/sync/engine/sequenced_model_worker.cc
diff --git a/components/sync/engine/sequenced_model_worker.cc b/components/sync/engine/sequenced_model_worker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ed84c5cd06991305e1a09c97c142872ae22b2b6c
--- /dev/null
+++ b/components/sync/engine/sequenced_model_worker.cc
@@ -0,0 +1,35 @@
+// Copyright 2012 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.
+
+#include "components/sync/engine/sequenced_model_worker.h"
+
+#include <utility>
+
+namespace syncer {
+
+SequencedModelWorker::SequencedModelWorker(
+    const scoped_refptr<base::SequencedTaskRunner>& runner,
+    ModelSafeGroup group)
+    : runner_(runner), group_(group) {}
+
+void SequencedModelWorker::ScheduleWork(base::OnceClosure work) {
+  if (runner_->RunsTasksInCurrentSequence()) {
+    DLOG(WARNING) << "Already on sequenced task runner " << runner_;
+    std::move(work).Run();
+  } else {
+    runner_->PostTask(FROM_HERE, std::move(work));
+  }
+}
+
+ModelSafeGroup SequencedModelWorker::GetModelSafeGroup() {
+  return group_;
+}
+
+bool SequencedModelWorker::IsOnModelSequence() {
+  return runner_->RunsTasksInCurrentSequence();
+}
+
+SequencedModelWorker::~SequencedModelWorker() {}
+
+}  // namespace syncer