Enable use_once_callback on mojom GN rule by default

services/service_manager/tests/connect/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 21 matching lines @@
   ]
 }
 
 mojom("interfaces") {
   sources = [
     "connect_test.mojom",
   ]
   deps = [
     "//services/service_manager/public/interfaces",
   ]
+
+  # TODO(crbug.com/714018): Convert the implementation to use OnceCallback.
+  use_once_callback = false
 }
 
 service_manifest("manifest") {
   name = "connect_unittests"
   source = "connect_unittests_manifest.json"
 }
 
 service_manifest("connect_test_a_manifest") {
   name = "connect_test_a"
   source = "connect_test_app_a_manifest.json"
@@ skipping 108 matching lines @@
   embedded_services = [ ":manifest" ]
 
   standalone_services = [
     ":connect_test_app_manifest",
     ":connect_test_class_app_manifest",
     ":connect_test_exe_manifest",
     ":connect_test_package_manifest",
     ":connect_test_singleton_app_manifest",
   ]
 }