How to have Google Chrome Canary on Ubuntu?

As stated in the site you linked, Canary builds are not available for Linux.

The only release channels available for Linux are: Stable, Beta and Dev.

The reason for that is explained here:

Thanks for your interesting in testing out the latest and greatest builds of Chrome. There are logistical challenges that make creating/ deploying Linux bundles prohibitively expensive to do on a daily basis, which effectively makes a Linux Canary fairly unlikely for the foreseeable future. I'd encourage the community to use the PPA builds, those are fundamentally the same as what we would build save for a couple of plugins (PDF, Flash, FFMpeg).

Kind Regards,

Anthony Laforge Technical Program Manager Mountain View, CA