Chrome users increasing day by day. Many Webmasters and publishers uses Google Toolbar to see Pagerank of site they are surfing, However Google Toolbar is not available for Google Chrome Browser. So to check pagerank of any site either you have to find some pagerank service, or you have to switch browser just to check pagerank.
Finally if you are eager for more SEO extensions, Chrome SEO is a must have Extension for Google Chrome. It has features to display, Backlinks, Pages Indexed, Traffic & Rankings, Cached Versions, Domain details and many more.