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

components/sync/driver/data_type_manager_impl.cc

Index: components/sync/driver/data_type_manager_impl.cc
diff --git a/components/sync/driver/data_type_manager_impl.cc b/components/sync/driver/data_type_manager_impl.cc
index afb73b00404505dfe3c5ae3fc5b34a954b95ade3..071d4c42bd447bf55ce6432c90d7285eec89fed0 100644
--- a/components/sync/driver/data_type_manager_impl.cc
+++ b/components/sync/driver/data_type_manager_impl.cc
@@ -640,12 +640,6 @@
 
   DVLOG(1) << "Associating " << ModelTypeSetToString(types_to_associate);
   model_association_manager_.StartAssociationAsync(types_to_associate);
-}
-
-void DataTypeManagerImpl::OnSingleDataTypeWillStart(ModelType type) {
-  DCHECK(controllers_->find(type) != controllers_->end());
-  DataTypeController* dtc = controllers_->find(type)->second.get();
-  dtc->BeforeLoadModels(configurer_);
 }
 
 void DataTypeManagerImpl::OnSingleDataTypeWillStop(ModelType type,