From the ChangeLog of attachment 276110 [details]: mathml/MathMLInlineContainerElement.cpp: The base wrapper of the <msqrt> element is actually the last child in the render tree. Selecting the correct wrapper makes presentation/mo-form-dynamic.html pass. The <math> element does not have anonymous child but is already a RenderMathMLRow, so we remove the special case for it.
Created attachment 276322 [details] Patch
Committed r199497: <http://trac.webkit.org/changeset/199497>