             // which allows the content appear beneath the toolbars in the BrowserViewController
             webView.scrollView.layer.masksToBounds = false
             webView.navigationDelegate = navigationDelegate
-            helperManager = HelperManager(webView: webView)
 
             restore(webView)
 


private class HelperManager: NSObject, WKScriptMessageHandler {
    fileprivate var helpers = [String: TabHelper]()
    fileprivate weak var webView: WKWebView?

    init(webView: WKWebView) {
        self.webView = webView
    }

    @objc func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        for helper in helpers.values {

        // If this helper handles script messages, then get the handler name and register it. The Browser
        // receives all messages and then dispatches them to the right TabHelper.
        if let scriptMessageHandlerName = helper.scriptMessageHandlerName() {
            tab.webView?.configuration.userContentController.add(self, name: scriptMessageHandlerName)
        }
    }

