The idea is to compile Python to Javascript (technically a JS pre-compiler) using Rapydscript. Then include the generated script in the Chrome extension. The site above has a zip file with all the stuff inside.
I recommend using Rapydscript instead of Pyjamas. A Python script compiled with Rapydscript works like any other Chrome plugin.
Pyjamas scripts does not work well with Google Chrome (needs a special parameter when Chrome starts or server).