The original article it links to is far more useful. It not only covers other matters, it is far more nuanced on the topic picked up here:
http://www.networkworld.com/news/2011/061311-mark-shuttlewor...
The headline would be more accurate as "Google Chrome might replace Firefox in Ubuntu Linux, but not for at least a year"
Key quote: "That probably keeps us on Firefox for another year, at least, and we'll see from there," Shuttleworth said.