window.unload event not emitted

[orslumen]

When a different page is loaded, the window.unload event is not emitted.

For now I have added the following code at the top of Envjs.exchangeHTMLDocument in core.js:
try {
if (doc === window.document) {
event = doc.createEvent('HTMLEvents');
event.initEvent('unload', false, false);
window.dispatchEvent( event, false );
}
} catch (eee) {
log.debug('window unload event failed %s', eee);
//swallow
}

I am note sure though whether or not this code is in the right location... see orslumen@2c2027e