Geforce now WKWebView

import UIKit
import WebKit

class ViewController: UIViewController {

    var webView: WKWebView!
    var popupWebView: WKWebView!

    let userAgent = "Mozilla/5.0 (X11; CrOS x86_64 13099.19.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.33 Safari/537.36"

    override func viewDidLoad() {
        super.viewDidLoad()
        setupWebView()
        loadWebView()
    }

    func loadWebView() {
        if let url = URL(string: "https://play.geforcenow.com/") {
            let urlRequest = URLRequest(url: url)
            webView.load(urlRequest)
        }
    }

    func setupWebView() {
        let preferences = WKPreferences()
        preferences.javaScriptEnabled = true
        preferences.javaScriptCanOpenWindowsAutomatically = true

        let configuration = WKWebViewConfiguration()
        configuration.preferences = preferences

        webView = WKWebView(frame: view.bounds, configuration: configuration)
        webView.customUserAgent = userAgent
        webView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        webView.uiDelegate = self
        webView.navigationDelegate = self

        view.addSubview(webView)
    }

}

extension ViewController: WKUIDelegate, WKNavigationDelegate {
    //MARK: Creating new webView for popup
    func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? {

        popupWebView = WKWebView(frame: view.bounds, configuration: configuration)
        popupWebView!.customUserAgent = userAgent
        popupWebView!.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        popupWebView!.navigationDelegate = self
        popupWebView!.uiDelegate = self

        let closeButton = UIButton(type: .close)
        closeButton.frame = CGRect(x: view.bounds.width - 66, y: 16, width: 50, height: 50)
        closeButton.addTarget(self, action: #selector(closeTapped), for: .touchUpInside)

        popupWebView.addSubview(closeButton)

        view.addSubview(popupWebView!)
        return popupWebView!
    }
    //MARK: To close popup
    func webViewDidClose(_ webView: WKWebView) {
        if webView == popupWebView {
            popupWebView?.removeFromSuperview()
            popupWebView = nil
        }
    }

    @objc func closeTapped(sender: Any) {
        webViewDidClose(popupWebView)
    }
}