Which GUI library does Google Chrome use?
On Linux it uses GTK+, on Mac OS X Cocoa, and on Windows a custom views library, see http://www.youtube.com/watch?v=WsvNebq1dRg and also documents from http://dev.chromium.org:
As of May 2014 Google Chrome uses it's own custom UI stack called Aura. This is currently the case for all platforms except OSX.
References:
You probably want their document entitled "Conventions and patterns for multi-platform development." Your answer is
Mac -> Cocoa,Linux -> GTK,Windows -> Their own custom "Windows Views"You'll also see have an experimental "GTK Views", so it sounds like they're aiming for their own abstraction?