There are problems if -webkit-writing-mode is vertical-rl, vertical-lr or horizontal-bt.
Created attachment 206320 [details] Test case
Created attachment 206655 [details] Patch
Comment on attachment 206655 [details] Patch r=me
Comment on attachment 206655 [details] Patch Clearing flags on attachment: 206655 Committed r153723: <http://trac.webkit.org/changeset/153723>
All reviewed patches have been landed. Closing bug.