Initial commit

ext/src/shim/messageBridge.js

@@ -0,0 +1,15 @@
+"use strict";
+
+export function onMessage (listener) {
+	document.addEventListener("__castMessage", ev => {
+		listener(JSON.parse(ev.detail));
+	});
+}
+
+export function sendMessage (message) {
+	const event = new CustomEvent("__castMessageResponse", {
+		detail: message
+	});
+
+	document.dispatchEvent(event);
+}