Enable use_once_callback on mojom GN rule by default

components/nacl/common/BUILD.gn

 # Copyright 2015 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("//build/config/features.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
 if (enable_nacl) {
   # This is separate so it can be used by ../broker:nacl64.
   static_library("minimal") {
@@ skipping 97 matching lines @@
   source_set("nacl_error_code") {
     sources = [
       "//native_client/src/trusted/service_runtime/nacl_error_code.h",
     ]
   }
 
   mojom("mojo_bindings") {
     sources = [
       "nacl.mojom",
     ]
-
-    use_once_callback = true
   }
 }
 
 # Depending on this allows targets to unconditionally include
 # nacl_process_type.h without testing whether nacl is enabled.
 source_set("process_type") {
   public = [
     "nacl_process_type.h",
   ]
 
   deps = [
     "//content/public/common",
   ]
 }
 
 static_library("switches") {
   sources = [
     "nacl_switches.cc",
     "nacl_switches.h",
   ]
 }