Chrome 28 is available now on the stable channel:

http://googlechromereleases.blogspot.com/2013/07/stable-chan...

The update is rolling out gradually. If you would like to make sure you're on the latest version, you can select "About Google Chrome" from the "Chrome" menu on Mac. That will take you to a page that shows you which version you're running and checks for updates.

As the release blog mentions, the Flash update is rolling out via the component updater, which updates Flash independently of the rest of Chrome.