I'm sometimes getting a crash when leaving a page, while a video is playing. This can happen when there is an asynchronous event invoked from a worker thread, accessing the media player object after it has been deleted.
Created attachment 248417 [details] Patch
Thanks for reviewing :)
Comment on attachment 248417 [details] Patch Clearing flags on attachment: 248417 Committed r181805: <http://trac.webkit.org/changeset/181805>
All reviewed patches have been landed. Closing bug.
I don't know if it is related but I have created bug 143088 for a crash when page is left/closed while video is loading (not yet playing).