Web shell test to go back and forward.

ios/web/public/test/http_server_util.h

+// Copyright 2016 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 IOS_WEB_PUBLIC_TEST_HTTP_SERVER_UTIL_H_
+#define IOS_WEB_PUBLIC_TEST_HTTP_SERVER_UTIL_H_
+
+#import <map>
+
+#include "url/gurl.h"
+
+namespace web {
+namespace test {
+
+// Sets up a web::test::HttpServer with a simple HtmlResponseProvider. The
+// HtmlResponseProvider will use the |responses| map to resolve URLs.
+void SetUpSimpleHttpServer(std::map<GURL, std::string> responses);
+
+}  // namespace test
+}  // namespace web
+
+#endif  // IOS_WEB_PUBLIC_TEST_HTTP_SERVER_UTIL_H_