main frame - didCommitLoadForFrame
frame "iframe" - didStartProvisionalLoadForFrame
main frame - didFinishDocumentLoadForFrame
-main frame - didHandleOnloadEventsForFrame
frame "iframe" - didFailProvisionalLoadWithError
+main frame - didHandleOnloadEventsForFrame
main frame - didFinishLoadForFrame
Test for https://bugs.webkit.org/show_bug.cgi?id=17360 REGRESSION: mp4 file downloaded from server is downloaded as html.