Crossrider get handler in Firefox Extention

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We cannot get the windows handle when we compile with crossrider? it does work fine when compile in firefox console.
other example code that works fine in console does not work with crossrider compiler. How can we get the handler.
var win = Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator).getMostRecentWindow("navigator:browser");
var basewindow = win.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsIWebNavigation)
.QueryInterface(Ci.nsIDocShellTreeItem)
.treeOwner
.QueryInterface(Ci.nsIInterfaceRequestor)
.nsIBaseWindow;
var nativehandle = basewindow.nativeHandle;