Link Prefetching was in Firefox 1.0 and DNS Prefetching was added in Firefox 3.5. Both were supported in the first release of Chrome, but DNS Prefetching hadn't ratified as a standard yet. The first stable release of Chrome was on December 11th, 2008. Firefox 1.0 came out on November 9th, 2004 and Firefox 3.5 came out on June 30th, 2009. Firefox 2 (October 24, 2006) already had support for the control headers for DNS Prefetching, but the standard wasn't ratified until later, which is when Firefox brought it into support.
That's not to say that Chrome didn't have different approaches to predicting and triggering prefetching compared to Firefox, and that in some ways those methods were better, but both Link Prefetching and DNS Prefetching were ideas before Chrome exists, Link Prefetching was ratifed and in Firefox before Chrome existed, and DNS Prefetching was shipped in Firefox as soon as the standard was ratified (Chrome shipped it in the first release before the standards process had concluded).
Link Prefetching was in Firefox 1.0 and DNS Prefetching was added in Firefox 3.5. Both were supported in the first release of Chrome, but DNS Prefetching hadn't ratified as a standard yet. The first stable release of Chrome was on December 11th, 2008. Firefox 1.0 came out on November 9th, 2004 and Firefox 3.5 came out on June 30th, 2009. Firefox 2 (October 24, 2006) already had support for the control headers for DNS Prefetching, but the standard wasn't ratified until later, which is when Firefox brought it into support.
That's not to say that Chrome didn't have different approaches to predicting and triggering prefetching compared to Firefox, and that in some ways those methods were better, but both Link Prefetching and DNS Prefetching were ideas before Chrome exists, Link Prefetching was ratifed and in Firefox before Chrome existed, and DNS Prefetching was shipped in Firefox as soon as the standard was ratified (Chrome shipped it in the first release before the standards process had concluded).