Created attachment 633199 [details] [diff] [review]
nsBrowserAccess is (if I understood the code correctly) only used to open links with custom target attributes in a new window or new tab. We should continue to use about:blank as default here instead of about:newtab because that new docShell/window will be used to load a new link in it and there's no need to load about:newtab in there.
While working on bug 753448 I noticed the following assertion:
This happens because we're opening a new tab and will be loading about:newtab and thus swapping a preloaded page. So it's actually more a timing issue that we didn't hit this assertion so far, I think.
Comment on attachment 633199 [details] [diff] [review]
Good catch; the only caller that passes null that I could find was nsContentTreeOwner::ProvideWindow, which indeed really specifically wants about:blank.
Thanks for the quick review!