Code review comment for lp:~abreu-alexandre/oxide/donottrack

Thanks, I've left some comments inline.

Also, the test is missing a few bits:

- It should verify that the default is off.
- It should check that the notify signal is emitted when you toggle it.
- What happens to window.navigator.doNotTrack if you change the setting without reloading the page? Does it update automatically? If it does, then that should be tested.