Web shell test to go back and forward.

ios/web/public/test/http_server_util.mm

+// 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.
+
+#include "ios/web/public/test/http_server_util.h"
+
+#import "ios/web/public/test/http_server.h"
+#include "ios/web/public/test/response_providers/html_response_provider.h"
+
+namespace web {
+namespace test {
+
+void SetUpSimpleHttpServer(std::map<GURL, std::string> responses) {
+  web::test::HttpServer& server = web::test::HttpServer::GetSharedInstance();
+  DCHECK(server.IsRunning());
+  std::unique_ptr<web::ResponseProvider> provider;
+  provider.reset(new HtmlResponseProvider(responses));
+
+  server.RemoveAllResponseProviders();
+  server.AddResponseProvider(provider.release());
+}
+
+}  // namespace test
+}  // namespace web