I have removed this and it only throw one error on initial test ([see error line](https://github.com/dojo/dojo/blob/master/dojo.js#L1609)).  I've updated this line from window.setTimeout to global.setTimeout.  I will need to test it with a bunch of of different classes to see if it breaks anything else.

The problem is that there are a few methods that are normally accessed via window (eg. setTimeout, setInterval, localStorages, ...etc) that are still available in workers but via the worker global, rather than window.