We fail to clean all the renderers while running the following tests: LayoutTests/fast/regions/region-element-display-change.html LayoutTests/fast/regions/region-element-display-restriction.html LayoutTests/fast/regions/table-caption-as-region.html
> LayoutTests/fast/regions/table-caption-as-region.html Moved under bug 164284
http://trac.webkit.org/changeset/208281 fixed the other issues too.