Add support for HTTP handlers that are in self-contained apps. Also add an example app.

services/http_server/public/http_server_util.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.
+
+#ifndef SERVICES_HTTP_SERVER_PUBLIC_HTTP_SERVER_UTIL_H_
+#define SERVICES_HTTP_SERVER_PUBLIC_HTTP_SERVER_UTIL_H_
+
+#include "services/http_server/public/http_response.mojom.h"
+
+namespace mojo {
+
+// Helper method to create an HttpResponse given the status code and body.
+HttpResponsePtr CreateHttpResponse(uint32_t status_code,
+                                   const std::string& body);
+}  // namespace mojo
+
+#endif  // SERVICES_HTTP_SERVER_PUBLIC_HTTP_SERVER_UTIL_H_