In DumpRenderTree/mac/DumpRenderTree.mm, some NSUserDefaults are set in resetDefaultsToConsistentValues: http://trac.webkit.org/browser/trunk/Tools/DumpRenderTree/mac/DumpRenderTree.mm#L391 AFAICT, we don't do this with Chromium's DRT (although we did on test_shell). I would expect this to cause all sorts of test differences with the mac results, but maybe not? Should we set these? I don't really know what these settings do.
Marking test failures as WontFix. Bug is still accessible and recording in TestExpectations.