public static void EnableFileDownloading(this OperaOptions options, string downloadDir)
{
options.AddLocalStatePreference("profile.default_content_settings.popups", 0);
options.AddLocalStatePreference("download.prompt_for_download", "false");
options.AddLocalStatePreference("download.default_directory", downloadDir);
options.AddLocalStatePreference("plugins.plugins_disabled", new[] { "Chrome PDF Viewer" });
}