[whatwg] Update to the Adoption Agency Algorithm

[Blake Kaplan]

David Hyatt wrote:
> BTW, we tried to add <span> as an inline that should be reopened (like 
> <font> and <b> etc.) and it broke some of our layout tests (snippets 
> of real-world Web sites).  <span> clearly does not always reopen in 
> WinIE and Firefox, so for now we are having to leave it out.
It never reopens in Firefox currently (I'm not sure of the original 
reasoning behind this), but I believe this is partially because a 
significant number of web pages treat <span> as a true block, like 
<div>. We've also seen sites give spans absolute positioning on pages, 
which means that reopening them will probably break those pages. 
Unfortunately, it seems that <span> is a half-block (at least in Gecko) 
with the worst behaviors of both worlds.

-- 
Blake Kaplan