[USS] Break NonBlockingDataTypeController into UI specific one and non-UI specific one

components/sync_driver/ui_model_type_controller.h

Index: components/sync_driver/ui_model_type_controller.h
diff --git a/components/sync_driver/ui_model_type_controller.h b/components/sync_driver/ui_model_type_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..d0648518eb770c355d2cb9ad150ded98108d07de
--- /dev/null
+++ b/components/sync_driver/ui_model_type_controller.h
@@ -0,0 +1,43 @@
+// Copyright 2016 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_DRIVER_UI_MODEL_TYPE_CONTROLLER_H_
+#define COMPONENTS_SYNC_DRIVER_UI_MODEL_TYPE_CONTROLLER_H_
+
+#include "components/sync_driver/non_blocking_data_type_controller.h"
+
+namespace sync_driver {
+class SyncClient;
+}
+
+namespace sync_driver_v2 {
+
+// Implementation for Unified Sync and Storage datatypes that reside on the UI
+// thread.
+class UIModelTypeController : public NonBlockingDataTypeController {
+ public:
+  UIModelTypeController(
+      const scoped_refptr<base::SingleThreadTaskRunner>& ui_thread,
+      const base::Closure& error_callback,
+      syncer::ModelType model_type,
+      sync_driver::SyncClient* sync_client);
+
+ protected:
+  ~UIModelTypeController() override;
+
+  void RunOnUIThread(const tracked_objects::Location& from_here,
+                     const base::Closure& task) override;
+
+ private:
+  // NonBlockingDataTypeController implementations.
+  // Since this is UI model type controller, we hide this function here.
+  bool RunOnModelThread(const tracked_objects::Location& from_here,
+                        const base::Closure& task) override;
+
+  DISALLOW_COPY_AND_ASSIGN(UIModelTypeController);
+};
+
+}  // namespace sync_driver_v2
+
+#endif  // COMPONENTS_SYNC_DRIVER_UI_MODEL_TYPE_CONTROLLER_H_