As of r152607, WebCore::MediaControlTextTrackContainerElement::updateDisplay() will occasionally ASSERT on a debug build. This usually happens two or so times on the test bots per run. See for example: http://build.webkit.org/results/Apple%20MountainLion%20Debug%20WK1%20(Tests)/r152607%20(8869)/media/track/track-remove-quickly-crash-log.txt
This test got removed in favor of WPT with this: https://github.com/WebKit/WebKit/commit/0f2d99d8d5683aa6c67bba585448331755dd9a68 * LayoutTests/media/track/track-remove-quickly.html: Same name on WPT * LayoutTests/media/track/track-remove-quickly-expected.txt: WPT test is passing since last four years (last changed by Darin - expected file). https://searchfox.org/wubkat/search?q=track-remove-quickly&path=&case=false®exp=false Marking this 'RESOLVED CONFIGURATION CHANGED'. @Eric - reopen if you think we need to do anything here.