What Are the necessary change for plugin that has a theme

previously, we have to do the following;

    public class MyPluginViewEngine : ThemeableRazorViewEngine
    {
        public MyPluginViewEngine()
        {
            ViewLocationFormats = new[] { "~/Plugins/Nop.Plugin.MyPlugin/Views/{0}.cshtml" };
            PartialViewLocationFormats = new[] { "~/Plugins/Nop.Plugin.MyPlugin/Views/{0}.cshtml" };
        }
    }

in the new 4 release what we must do,

please help.