Web shell test to go back and forward.

ios/web/shell/test/navigation_test_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/shell/test/navigation_test_util.h"
+
+#import "ios/web/public/navigation_manager.h"
+#import "ios/web/public/web_state/web_state.h"
+#import "ios/web/shell/test/web_shell_test_util.h"
+
+using web::NavigationManager;
+
+namespace web {
+namespace navigation_test_util {
+// TODO(crbug.com/604902): Refactor these utilities into objects that can be
+// shared accross the web shell and Chrome.
+
+void LoadUrl(GURL url) {
+  ViewController* view_controller =
+      web::web_shell_test_util::GetCurrentViewController();
+
+  NavigationManager* navigation_manager =
+      [view_controller webState]->GetNavigationManager();
+  NavigationManager::WebLoadParams params(url);
+  params.transition_type = ui::PAGE_TRANSITION_TYPED;
+  navigation_manager->LoadURLWithParams(params);
+}
+
+}  // namespace navigation_test_util
+}  // namespace web