WebKit2 provides the function WKBundleNodeHandleSetHTMLInputElementAutofilled as a way of setting the "autofilled" flag on an input element. It should also provide a counterpart getter function to test whether that flag is set.
Created attachment 72377 [details] Patch to provide WKBundleNodeHandleGetHTMLInputElementAutofilled
Committed in http://trac.webkit.org/changeset/70916