Not quite sure on the best approach here, but my gut it questioning whether it is a good idea to have a chunk of logic here and below that is specific to /firefox/new/ in `global.js`. I would perhaps edge toward keeping things separate, and letting the tracking here handle the other download buttons. 

/firefox/new/ could probably still make use of the global functions here, but if that page has specific behavior then maybe keep it in that page.

Any feelings on this one, @jpetto?