We have a layout error when there is a shape applied on the second region,and it has a negative 'top' coordinate. Since shapeInsideInfo::shapeLogicalTop() can return negative numbers, we need to check for it we're positioning the first line in the region.
Created attachment 215192 [details]
Comment on attachment 215192 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=215192&action=review
> + if (!shapeTopOffset && (0 < shapeInsideInfo->shapeLogicalTop()))
We don't typically put the constants on the left. I'd change this to shapeInsideInfo->shapeLogicalTop() > 0