[whatwg] Proposal: Add window.getLastError (or modify invocation arguments of window.onerror)

[James Greene]

Full proposal details:
    https://gist.github.com/3ded0f6e7f0a658b9394

P.S. I had no idea what "product" to file this under in the W3C Bugzilla,
so it has NOT been filed there. I HAVE posted a new topic to the Forums but
it is still awaiting moderator approval.

Sincerely,
    James Greene