Create MainWindow folder to match Mac folder structure.

iOS/MainWindow/Article/WrapperScriptMessageHandler.swift

@@ -0,0 +1,25 @@
+//
+//  WrapperScriptMessageHandler.swift
+//  NetNewsWire-iOS
+//
+//  Created by Maurice Parker on 2/4/20.
+//  Copyright © 2020 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import WebKit
+
+final class WrapperScriptMessageHandler: NSObject, WKScriptMessageHandler {
+
+	// We need to wrap a message handler to prevent a circlular reference
+	private weak var handler: WKScriptMessageHandler?
+
+	init(_ handler: WKScriptMessageHandler) {
+		self.handler = handler
+	}
+
+	func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
+		handler?.userContentController(userContentController, didReceive: message)
+	}
+
+}