[Sync] Make directory types registration explicit in ModelTypeRegistry

components/sync/driver/glue/sync_backend_host_impl.cc

Index: components/sync/driver/glue/sync_backend_host_impl.cc
diff --git a/components/sync/driver/glue/sync_backend_host_impl.cc b/components/sync/driver/glue/sync_backend_host_impl.cc
index ff1a70e7738c43e668f251314436bdb64cc29579..0106db4c35c75d85980b0eba0576772245170838 100644
--- a/components/sync/driver/glue/sync_backend_host_impl.cc
+++ b/components/sync/driver/glue/sync_backend_host_impl.cc
@@ -90,15 +90,17 @@ void SyncBackendHostImpl::UpdateCredentials(
                             credentials));
 }
 
+void SyncBackendHostImpl::StartConfiguration() {
+  sync_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&SyncBackendHostCore::DoStartConfiguration, core_));
+}
+
 void SyncBackendHostImpl::StartSyncingWithServer() {
   SDVLOG(1) << "SyncBackendHostImpl::StartSyncingWithServer called.";
 
-  ModelSafeRoutingInfo routing_info;
-  registrar_->GetModelSafeRoutingInfo(&routing_info);
-
   sync_task_runner_->PostTask(
       FROM_HERE, base::Bind(&SyncBackendHostCore::DoStartSyncing, core_,
-                            routing_info, sync_prefs_->GetLastPollTime()));
+                            sync_prefs_->GetLastPollTime()));
 }
 
 void SyncBackendHostImpl::SetEncryptionPassphrase(const std::string& passphrase,
@@ -211,6 +213,15 @@ void SyncBackendHostImpl::ConfigureDataTypes(ConfigureParams params) {
                             base::Passed(&params)));
 }
 
+void SyncBackendHostImpl::RegisterDirectoryDataType(ModelType type,
+                                                    ModelSafeGroup group) {
+  model_type_connector_->RegisterDirectoryType(type, group);
+}
+
+void SyncBackendHostImpl::UnregisterDirectoryDataType(ModelType type) {
+  model_type_connector_->UnregisterDirectoryType(type);
+}
+
 void SyncBackendHostImpl::EnableEncryptEverything() {
   sync_task_runner_->PostTask(
       FROM_HERE,
@@ -234,11 +245,12 @@ void SyncBackendHostImpl::ActivateNonBlockingDataType(
   registrar_->RegisterNonBlockingType(type);
   if (activation_context->model_type_state.initial_sync_done())
     registrar_->AddRestoredNonBlockingType(type);
-  model_type_connector_->ConnectType(type, std::move(activation_context));
+  model_type_connector_->ConnectNonBlockingType(type,
+                                                std::move(activation_context));
 }
 
 void SyncBackendHostImpl::DeactivateNonBlockingDataType(ModelType type) {
-  model_type_connector_->DisconnectType(type);
+  model_type_connector_->DisconnectNonBlockingType(type);
 }
 
 UserShare* SyncBackendHostImpl::GetUserShare() const {