How to get focus to a Chrome tab which created desktop notification?

You can just place window.focus() in Google Chrome. It will focus to that window when clicked.

var n = window.webkitNotifications.createNotification('ico.gif', 'Title', 'Text');
n.onclick = function(x) { window.focus(); this.close(); };
n.show();

I opened the inspector in Gmail, added the above code, moved to a different tab, and ran it. The notification appeared and once clicked, it brought me back to Gmail.