Revert of [Sync] Make directory types registration explicit in ModelTypeRegistry

components/sync/driver/directory_data_type_controller.cc

Index: components/sync/driver/directory_data_type_controller.cc
diff --git a/components/sync/driver/directory_data_type_controller.cc b/components/sync/driver/directory_data_type_controller.cc
index 933a328ead72b01cf05911ed3830ab8201bb35f2..86fdd7350e1c831a3c25f2b59c8e989fed95226f 100644
--- a/components/sync/driver/directory_data_type_controller.cc
+++ b/components/sync/driver/directory_data_type_controller.cc
@@ -34,31 +34,6 @@
   return false;
 }
 
-void DirectoryDataTypeController::BeforeLoadModels(
-    ModelTypeConfigurer* configurer) {
-  configurer->RegisterDirectoryDataType(type(), model_safe_group_);
-}
-
-void DirectoryDataTypeController::RegisterWithBackend(
-    base::Callback<void(bool)> set_downloaded,
-    ModelTypeConfigurer* configurer) {}
-
-void DirectoryDataTypeController::ActivateDataType(
-    ModelTypeConfigurer* configurer) {
-  DCHECK(CalledOnValidThread());
-  // Tell the backend about the change processor for this type so it can
-  // begin routing changes to it.
-  configurer->ActivateDirectoryDataType(type(), model_safe_group_,
-                                        GetChangeProcessor());
-}
-
-void DirectoryDataTypeController::DeactivateDataType(
-    ModelTypeConfigurer* configurer) {
-  DCHECK(CalledOnValidThread());
-  configurer->DeactivateDirectoryDataType(type());
-  configurer->UnregisterDirectoryDataType(type());
-}
-
 void DirectoryDataTypeController::GetAllNodes(
     const AllNodesCallback& callback) {
   std::unique_ptr<base::ListValue> node_list = GetAllNodesForTypeFromDirectory(
@@ -82,6 +57,25 @@
   callback.Run(type(), counters);
 }
 
+void DirectoryDataTypeController::RegisterWithBackend(
+    base::Callback<void(bool)> set_downloaded,
+    ModelTypeConfigurer* configurer) {}
+
+void DirectoryDataTypeController::ActivateDataType(
+    ModelTypeConfigurer* configurer) {
+  DCHECK(CalledOnValidThread());
+  // Tell the backend about the change processor for this type so it can
+  // begin routing changes to it.
+  configurer->ActivateDirectoryDataType(type(), model_safe_group_,
+                                        GetChangeProcessor());
+}
+
+void DirectoryDataTypeController::DeactivateDataType(
+    ModelTypeConfigurer* configurer) {
+  DCHECK(CalledOnValidThread());
+  configurer->DeactivateDirectoryDataType(type());
+}
+
 // static
 std::unique_ptr<base::ListValue>
 DirectoryDataTypeController::GetAllNodesForTypeFromDirectory(