`<link rel="prefetch">` should fire load/error events

[bzbarsky]

Chrome already does this in some cases, apparently. Testcase:

data:text/html,<link rel="prefetch" href="http://example.com" onload="alert(1)" onerror="alert(2)">

Not sure whether it ever fires error here.

Sites are working around the lack of these events by doing prefetching via img/object/etc hacks...

Note the discussion #1142 though.

[bzbarsky]

Ah, it was pointed out to me that the spec here is https://w3c.github.io/resource-hints/#load-and-error-events

[domenic]

I'd like to roll this into #1142. In #1142 (comment) I outlined what I think the fix is.