chrome is not defined in Firefox based browser

In following code of the online version (app.js), it checks `chrome.account360`, where chrome is undefined.

```js
  return s ||
  (
    chrome.account360 ? chrome.account360.getMID(t => {
      t ? s = t : e().then(t => s = t)
    }) : e().then(t => s = t)
  )
```