What to install before the workshop
Follow the instructions for "Building" (under "Getting the Code") here: http://www.chromium.org/developers
It'll take about 30 minutes to complete the instructions, but the first build will take about 10 hours to finish running. (Subsequent builds will take a few seconds to a few minutes.) You can just let the build finish running overnight (make sure your computer won't automatically go to sleep after a while!).
If you can't do the build before the workshop, you can also contribute to Chromium by having Google's server farm build and test your code (i.e. buildbots).