This is currently implemented for editable content. It should work for both. <rdar://problem/17760073>
Created attachment 235698 [details] Patch
Comment on attachment 235698 [details] Patch Attachment 235698 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/6332538612088832 New failing tests: media/track/add-and-remove-track.html
Created attachment 235704 [details] Archive of layout-test-results from webkit-ews-12 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-12 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.5
Committed revision 171782.