The reducted html works not as expected with webkit r39286
It does in Firefox 3.0.1
Created attachment 26013 [details]
reduced html file
Confirmed with r39230
i hoped the new html5 parsing engine (r64727) would finally solve this
problem, but it's not the case.
What exactly is the problem here? Both Firefox and Safari render the lines as red, black, green. With nightly r64816, the DOM is even exactly the same as in Firefox 3.6.6.
I think the difference with Firefox 3.0.1 was caused by it lacking support for <video> element - <source> is part of it, and it has special requirements on where it can appear in the document.
As far as I can tell, this behaves correctly.