> WebKit (and consequently Chrome) have a "preload scanner" (you can Google for those words to find posts about it) that attempt to parallelize the former in all cases.

Everyone does, as far as I'm aware. (And I'm pretty sure this is a case where one can invoke the Opera-did-it-first meme[0].)

[0]: http://w3cmemes.tumblr.com/post/62942106027/if-you-can-think...