Expose requireAsync method and make it more robust

extensions/renderer/api/mojo_private/mojo_private_unittest.cc

 // 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.
 
 #include "extensions/renderer/api_test_base.h"
 
 #include "gin/modules/module_registry.h"
 
 // A test launcher for tests for the mojoPrivate API defined in
 // extensions/test/data/mojo_private_unittest.js.
@@ skipping 27 matching lines @@
 TEST_F(MojoPrivateApiTest, DefineModuleDoesNotExist) {
   ASSERT_NO_FATAL_FAILURE(
       RunTest("mojo_private_unittest.js", "testDefineModuleDoesNotExist"));
   EXPECT_EQ(0u, module_registry()->available_modules().count("testModule"));
   EXPECT_EQ(0u,
             module_registry()->available_modules().count("does not exist!"));
   EXPECT_EQ(1u, module_registry()->unsatisfied_dependencies().count(
                     "does not exist!"));
 }
 
+TEST_F(MojoPrivateApiTest, RequireAsync) {
+  ASSERT_NO_FATAL_FAILURE(
+      RunTest("mojo_private_unittest.js", "testRequireAsync"));
+}
+
+TEST_F(MojoPrivateApiTest, DefineAndRequire) {
+  ASSERT_NO_FATAL_FAILURE(
+      RunTest("mojo_private_unittest.js", "testDefineAndRequire"));
+}
+
 }  // namespace extensions