Pepper: Make Mojo test more strict.

ppapi/tests/mojo/test_mojo.cc

 // 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.
 
 #include "ppapi/tests/mojo/test_mojo.h"
 
 #include "third_party/mojo/src/mojo/public/cpp/system/message_pipe.h"
 
 REGISTER_TEST_CASE(Mojo);
 
 TestMojo::TestMojo(TestingInstance* instance) : TestCase(instance) { }
 bool TestMojo::Init() {
   return true;
 }
 
 void TestMojo::RunTests(const std::string& filter) {
   RUN_TEST(CreateMessagePipe, filter);
 }
 
 std::string TestMojo::TestCreateMessagePipe() {
-  mojo::MessagePipe pipe;
+  MojoHandle h0;
+  MojoHandle h1;
+  ASSERT_EQ(MOJO_RESULT_OK, MojoCreateMessagePipe(NULL, &h0, &h1));
   PASS();
 }