Enable use_once_callback on mojom GN rule by default

services/service_manager/tests/shutdown/BUILD.gn

 # 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.
 
 import("//services/catalog/public/tools/catalog.gni")
 import("//services/service_manager/public/cpp/service.gni")
 import("//services/service_manager/public/service_manifest.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
@@ skipping 17 matching lines @@
   data_deps = [
     ":shutdown_client",
     ":shutdown_service",
   ]
 }
 
 mojom("interfaces") {
   sources = [
     "shutdown_unittest.mojom",
   ]
+
+  # TODO(crbug.com/714018): Convert the implementation to use OnceCallback.
+  use_once_callback = false
 }
 
 service_manifest("shutdown_unittest_manifest") {
   name = "shutdown_unittest"
   source = "shutdown_unittest_manifest.json"
 }
 
 service_manifest("shutdown_service_manifest") {
   name = "shutdown_service"
   source = "shutdown_service_manifest.json"
@@ skipping 31 matching lines @@
 }
 
 catalog("catalog") {
   embedded_services = [ ":shutdown_unittest_manifest" ]
 
   standalone_services = [
     ":shutdown_client_manifest",
     ":shutdown_service_manifest",
   ]
 }