[Sync] Convert DTCs to be not RefCounted and NonThreadSafe.

components/search_engines/search_engine_data_type_controller.h

Index: components/search_engines/search_engine_data_type_controller.h
diff --git a/components/search_engines/search_engine_data_type_controller.h b/components/search_engines/search_engine_data_type_controller.h
index 62de83c715a72b5f5fd93792b56df546cbf9957e..4e3eb4139f9c5854dac9059b9625f140c09ae37d 100644
--- a/components/search_engines/search_engine_data_type_controller.h
+++ b/components/search_engines/search_engine_data_type_controller.h
@@ -22,26 +22,21 @@ namespace browser_sync {
 class SearchEngineDataTypeController
     : public sync_driver::UIDataTypeController {
  public:
-  SearchEngineDataTypeController(
-      const scoped_refptr<base::SingleThreadTaskRunner>& ui_thread,
-      const base::Closure& error_callback,
-      sync_driver::SyncClient* sync_client,
-      TemplateURLService* template_url_service);
+  // |dump_stack| is called when an unrecoverable error occurs.
+  SearchEngineDataTypeController(const base::Closure& dump_stack,
+                                 sync_driver::SyncClient* sync_client,
+                                 TemplateURLService* template_url_service);
+  ~SearchEngineDataTypeController() override;
 
   TemplateURLService::Subscription* GetSubscriptionForTesting();
 
  private:
-  ~SearchEngineDataTypeController() override;
-
   // FrontendDataTypeController:
   bool StartModels() override;
   void StopModels() override;
 
   void OnTemplateURLServiceLoaded();
 
-  // A reference to the UI thread's task runner.
-  const scoped_refptr<base::SingleThreadTaskRunner> ui_thread_;
-
   // A pointer to the template URL service that this data type will use.
   TemplateURLService* template_url_service_;