Mojo: Add a trivial end-to-end (in-process) test of Mojo shell.

mojo/services/test_service/test_service_impl.h

+// 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 "mojo/public/cpp/application/application.h"
+#include "mojo/public/cpp/system/macros.h"
+#include "mojo/services/test_service/test_service.mojom.h"
+
+namespace mojo {
+namespace test {
+
+class TestServiceImpl : public InterfaceImpl<ITestService> {
+ public:
+  TestServiceImpl();
+  virtual ~TestServiceImpl();
+
+  // |ITestService| methods:
+  virtual void Ping(const mojo::Callback<void()>& callback) MOJO_OVERRIDE;
+
+ private:
+  MOJO_DISALLOW_COPY_AND_ASSIGN(TestServiceImpl);
+};
+
+}  // namespace test
+}  // namespace mojo
+