Mojo JS bindings: flip the default value of use_new_js_bindings to true.

components/payments/mojom/BUILD.gn

 # Copyright 2017 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("mojom") {
   sources = [
     "payment_request.mojom",
   ]
+
+  # TODO(crbug.com/699569): Convert to use the new JS bindings.
+  use_new_js_bindings = false
 }
 
 mojom("mojom_parser") {
   sources = [
     "payment_manifest_parser.mojom",
   ]
 
   public_deps = [
     "//url/mojo:url_mojom_gurl",
   ]
 }
 
 mojom("mojom_payment_app") {
   sources = [
     "payment_app.mojom",
   ]
 
   public_deps = [
     ":mojom",
     "//mojo/common:common_custom_types",
     "//url/mojo:url_mojom_gurl",
   ]
 }