Currently, SessionStore.jsm / nsSessionStartup.js use mostly main thread synchronous I/O. Let's migrate them to background asynchronous I/O.

(In reply to David Rajchenbach Teller [:Yoric] from comment #0) > mostly main thread synchronous I/O That's not true... the only synchronous i/o left is reading sessionstore.js at startup (yes, bad but will require some re-thinking of session restore to get right). Writing that file out is async off main thread.

See also, bug 532150. Not that I disagree with using OS.File, just defending session restore :)

(In reply to Paul O'Shannessy [:zpao] from comment #1) > (In reply to David Rajchenbach Teller [:Yoric] from comment #0) > > mostly main thread synchronous I/O > > That's not true... the only synchronous i/o left is reading sessionstore.js > at startup (yes, bad but will require some re-thinking of session restore to > get right). Writing that file out is async off main thread. I was thinking of input. Good to know that there is already a bug on it. And I intend to port all of this to OS.File regardless :)

Well, I guess that's done.