Introduce mock test system for navigator content utils

Source/modules/navigatorcontentutils/testing/InternalsNavigatorContentUtils.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 InternalsNavigatorContentUtils_h
+#define InternalsNavigatorContentUtils_h
+
+namespace WebCore {
+
+class Document;
+class NavigatorContentUtilsClientMock;
+class Internals;
+
+class InternalsNavigatorContentUtils {
+public:
+    static void setNavigatorContentUtilsClientMock(Internals&, Document*);
+};
+
+} // namespace WebCore
+
+#endif // InternalsNavigatorContentUtils_h