The latest developer build of Chrome now includes an official option to install themes into Google Chrome. It was reported earlier this week by Neowin that Google is preparing to launch a theme gallery. It looks like this has happened with the release of build 18.104.22.168.
The option is offered under "Personal Stuff" and has the option to "Get Themes". Pressing the button redirects you to a webpage, that shows a whole array of new themes for Chrome.
Applying the theme is as simple as pressing the "Apply Theme" button below the chosen theme, and a ".crx" file is downloaded. A restart of Chrome is not required to apply the theme. To get this option, Chrome 22.214.171.124 must be installed, and you must be in the "Developer" build channel.
The release of this feature to the developer build channel indicates that a lot of work has been done, but there is still a lot to come. It seems to be very efficient and stable, and may progress to the main public builds in the near future.
Google Chrome is Google's flagship browser, based upon the Web Kit rendering engine, and touts the most minimal interface, and fastest browser start times.