Mojo JS bindings: change module loading solution.

mojo/public/interfaces/bindings/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("../../tools/bindings/mojom.gni")
 
 mojom("bindings") {
   visibility = []
   sources = [
     "interface_control_messages.mojom",
     "pipe_control_messages.mojom",
   ]
 
   export_class_attribute = "MOJO_CPP_BINDINGS_EXPORT"
   export_define = "MOJO_CPP_BINDINGS_IMPLEMENTATION"
   export_header = "mojo/public/cpp/bindings/bindings_export.h"
 }
+
+# TODO(yzshen): Remove this target and use the one above once
+# |use_new_js_bindings| becomes true by default.
+mojom("new_bindings") {
+  visibility = []
+  sources = [
+    "new_bindings/interface_control_messages.mojom",
+    "new_bindings/pipe_control_messages.mojom",
+  ]
+
+  use_new_js_bindings = true
+}