Enable use_once_callback on mojom GN rule by default

services/ui/public/interfaces/ime/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("//mojo/public/tools/bindings/mojom.gni")
 
 mojom("ime") {
   sources = [
     "ime.mojom",
   ]
 
   public_deps = [
     "//mojo/common:common_custom_types",
     "//ui/events/mojo:interfaces",
     "//ui/gfx/geometry/mojo",
     "//ui/gfx/range/mojo",
   ]
+
+  # TODO(crbug.com/714018): Convert the implementation to use OnceCallback.
+  use_once_callback = false
 }
 
 mojom("test_interfaces") {
   sources = [
     "ime_struct_traits_test.mojom",
   ]
 
   public_deps = [
     ":ime",
   ]
+
+  # TODO(crbug.com/714018): Convert the implementation to use OnceCallback.
+  use_once_callback = false
 }