I'm extracting this from bug 119038.
Created attachment 232578 [details]
mmh, it seems that the current msqrt/mroot code has bugs with dynamic modifications...
Created attachment 232606 [details]
So let's skip the tests for now. I'll try to make the patch of bug 119038 handles both the OpenTypeMATH and graphical drawing of radical.
Committed r169671: <http://trac.webkit.org/changeset/169671>