Re: Necko e10s specs

Mike Shaver wrote:
> Can one domain trigger a navigation/document.write/clear/etc. cause an
> onbeforeunload in a document on another domain to fire synchronously?

Gah.

beforeunload fires in the following cases right now:

1) Right after the script of a javascript: URI executes.  This could 
probably be made async from that execution if needed; it's already async 
from whatever started the load (modulo plug-ins, but we could change that).

2) window.close() is called.  This is in fact sync and the caller just 
needs to be the opener of the window; the page in the window might be 
from a different domain now.  This is moderately annoying.  Then again, 
they're already "same domain" for multi-process purposes in that one has 
a direct pointer to the window of the other, no?

3) We call CreateAboutBlankContentViewer while a document is loaded. 
This can happen when doing URI loads of URIs sent to us from outside the 
app (which I think should be ok) and on LoadHistoryEntry of an entry 
whose URI is javascript:.  This last can be triggered sync by a web 
page, but I don't think that can happen cross-domain (have to be able to 
do a history.go/back/forward on that webpage, and I _think_ that 
requires same-origin).

4) Doing a navigation on the docshell via setting window.location.  This 
would be sync and can happen cross-domain.  We should consider making it 
async, perhaps (just like link clicks and form submits already are).

5) document.open will do it, but that can't be called cross-domain, 
ever.  Or rather, it throws NS_ERROR_DOM_SECURITY_ERR if it is.

So if we make the close() and location= codepaths deal, I think we 
should be safe here.

-Boris