Previously, with early first paint enabled, nsXULWindow incorrectly loaded the
persisted window settings from about:blank and would only load them once.
Instead, load the settings before starting layout.
MozReview-Commit-ID: 6K4ofkbmHHb
--HG--
extra : rebase_source : 7bcd804cfabbd47ee5a747800a2ef81852213889