Mojo JS bindings: change module loading solution.

mojo/public/interfaces/bindings/tests/BUILD.gn

 # Copyright 2014 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("test_interfaces") {
   testonly = true
   sources = [
     "math_calculator.mojom",
     "no_module.mojom",
     "ping_service.mojom",
     "rect.mojom",
     "regression_tests.mojom",
     "sample_factory.mojom",
     "sample_interfaces.mojom",
     "sample_service.mojom",
     "scoping.mojom",
     "serialization_test_structs.mojom",
     "test_bad_messages.mojom",
     "test_constants.mojom",
     "test_data_view.mojom",
     "test_native_types.mojom",
     "test_structs.mojom",
     "test_sync_methods.mojom",
     "validation_test_interfaces.mojom",
   ]
   public_deps = [
+    ":echo",
     ":test_mojom_import",
     ":test_mojom_import2",
   ]
 }
 
 component("test_export_component") {
   testonly = true
   deps = [
     ":test_export",
   ]
@@ skipping 152 matching lines @@
   ]
 }
 
 mojom("test_no_sources") {
   testonly = true
 
   public_deps = [
     ":test_interfaces",
   ]
 }
+
+mojom("echo") {
+  testonly = true
+  sources = [
+    "echo.mojom",
+    "echo_import.mojom",
+  ]
+  use_new_js_bindings = true
+}