The attached testcase shows that repainting with a layoutDelta in effect is broken when an ancestor is transformed.
Created attachment 26585 [details]
Actually I think the testcase is showing an issue with LayoutState, not layoutDelta.
Created attachment 26595 [details]
Patch, LayoutTest changelog
I changed RenderBlock::layoutOnlyPositionedObjects() to use the same criteria as RenderBlock::layoutBlock() for disabling layoutState, because testing showed that layoutOnlyPositionedObjects() could be hit for a block with a reflection. I think this is the right thing to do.
Committing to http://svn.webkit.org/repository/webkit/trunk ...
See also bug 23233.