Web shell test to go back and forward.

ios/web/shell/test/utils/navigation_egutil.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_SHELL_TEST_NAVIGATION_EGUTIL_H_
+#define IOS_WEB_SHELL_TEST_NAVIGATION_EGUTIL_H_
+
+#import "ios/web/shell/view_controller.h"
+
+#include "url/gurl.h"
+
+namespace navigation_egutil {
+
+// Load |url| in current webState.
+void LoadURL(GURL url);
+
+}  // namespace navigation_egutil
+
+#endif  // IOS_WEB_SHELL_TEST_NAVIGATION_EGUTIL_H_