Why no SafeWeb for Chrome?!?

Have been reading posts re: no SafeWeb for Chrome that say Norton's been promising the utility for the browser for 2 years. The most recent update to NIS2011 has made the utility available to FF4 & IE9, but still no Chrome. McAfee's had a similar utility in place for Chrome for months now. What's up? How is it that McAfee can do what Norton can't seem to?