See http://build.webkit.org/results/Apple%20Mavericks%20Release%20WK1%20(Tests)/r169757%20(6523)/results.html
Marked the test as failing in r169761: http://trac.webkit.org/changeset/169761
This was fallout from the changes in RenderLayerCompositor::notifyIFramesOfCompositingChange() where we used to do a deep walk, and now do a shallow walk. I'll revert to the older code for now.
https://trac.webkit.org/r169777