Because <track>-related features are now RuntimeEnabled, we need to explicitly make them runable by DRT in order to be able to run the <track>-related layout tests.
Created attachment 112302 [details] Patch
Thanks for the hint, Adam!
Comment on attachment 112302 [details] Patch Clearing flags on attachment: 112302 Committed r98354: <http://trac.webkit.org/changeset/98354>
All reviewed patches have been landed. Closing bug.