IIRC, it uses the Trident rendering engine, but all the browser UX and chrome is custom. Most browsers are wrapping webkit today, does that make Opera and Safari clones of Chrome? Not sure.
Umm, Webkit spun out of Safari, so that would make Chrome the "clone" of Safari.
Which is rather your point. Chrome has made a lot of changes to Webkit over the years, and these days appears to be putting more effort into it than Apple is.
Implying that WebKit somehow stalled because Google forked it into Blink is silly. Apple and Google are both investing heavily in their browsers, just with different priorities. Doesn't take more than just looking at the WebKit blog to see that.
I use Safari by preference and wish Apple would push harder, but perhaps my attitude is a little unfair.
webkit/safari was spun off of KHTML/Konqueror, so would that make Safari a "clone" of Konqueror
edit: spelling