How can I update the development version Google Chrome?

Google Chrome in updated in Ubuntu via normal system update. The Unstable channel is actually the DEV Channel of Google Chrome.

Go to System -> Administration -> Update Manager and update your system and the Google Chrome would be updated to latest DEV release.

Or to selectively upgrade Google Chrome, run this command from the terminal:

sudo apt-get upgrade google-chrome-unstable

For me what worked is:

sudo apt-get upgrade google-chrome-stable

(instead of unstable)

In an attempt to make this out-of date question useful, Currently Chrome supports a number of different release channels. For Ubuntu Linux as of the date of writing these are:

Stable Channel: This channel has gotten the full testing and blessing of the Chrome test team, and is the best bet to avoid crashes and other issues. It's updated roughly every two-three weeks for minor releases, and every 6 weeks for major releases.

Beta Channel: If you are interested in seeing what's next, with minimal risk, Beta channel is the place to be. It's updated every week roughly, with major updates coming every six weeks, more than a month before the Stable channel will get them.

Dev Channel: Want to see what's happening quickly, then you want the Dev channel. The Dev channel gets updated once or twice weekly, and it shows what we're working on right now. There's no lag between major versions, whatever code we've got, you will get. While this build does get tested, it is still subject to bugs, as we want people to see what's new as soon as possible.

Source:

Chrome Release Channels