fix(web_ios): Not rendering when the browser back button is pressed.

react/index.web.js

 import { getJitsiMeetTransport } from '../modules/transport';
 
 import { App } from './features/app';
+import { Platform } from './features/base/react';
 
 const logger = require('jitsi-meet-logger').getLogger(__filename);
+const OS = Platform.OS;
 
 /**
  * Renders the app when the DOM tree has been loaded.
     ReactDOM.render(<App />, document.getElementById('react'));
 });
 
+// Workaround for the issue when returning to a page with the back button and
+// the page is loaded from the 'back-forward' cache on iOS which causes nothing
+// to be rendered.
+if (OS === 'ios') {
+    window.addEventListener('pageshow', event => {
+        // Detect pages loaded from the 'back-forward' cache
+        // (https://webkit.org/blog/516/webkit-page-cache-ii-the-unload-event/)
+        if (event.persisted) {
+            // Maybe there is a more graceful approach but in the moment of
+            // writing nothing else resolves the issue. I tried to execute our
+            // DOMContentLoaded handler but it seems that the 'onpageshow' event
+            // is triggered only when 'window.location.reload()' code exists.
+            window.location.reload();
+        }
+    });
+}
+
 /**
  * Stops collecting the logs and disposing the API when the user closes the
  * page.