FWIW we have the "wand" feature which will fill in, and submit, a form for you with previously used values (it's the key icon on the toolbar or ctrl+enter).
I know this is not quite the same implementation that other browsers have.
Your "wand" feature also adds a terrifically ugly yellow border to remembered inputs which developers have no way to prevent (like you can with WebKit by using outline: 0). I'm all for a constant UI to create a good UX but not when it can make a site look bad.
I know this is not quite the same implementation that other browsers have.