Google is only doing something to a single application, one which they have made from scratch (well, minus the webkit stuff) without major 3rd party contributions. Canonical, on the other hand, controls an entire distribution and all the applications it ships with. And most of those are from 3rd parties. So i really don't see the comparison here at all. That's the apples and oranges.
No announcement yet.
Google Replacing GTK2 With Aura In Chrome 35