https://bugs.webkit.org/show_bug.cgi?id=28241 caused media/video-controls-with-mutation-event-handler.html to begin crashing on Windows, eg. http://build.webkit.org/results/Windows%20Release%20(Tests)/r47770%20(3743)/results.html. The crash happens when the MediaControlVolumeSliderElement constructor calls setAttribute() in a page with registered mutation event listeners. setAttribute() causes a synchronous event to be fired immediately and the event destructor derefs the event target (the MediaControlVolumeSliderElement) so the element is destroyed before the constructor returns.
Created attachment 38598 [details] proposed patch
http://trac.webkit.org/changeset/47774