Created attachment 268128 [details]
Attached test case should scroll to 0 (or -200 in Firefox), not 10. The border is messing things up.
I think this line maps into local coordinates, but those include the border box:
Created attachment 412317 [details]
Looks like there are a few one pixel differences and some new passes. I should be able to update the results for these tomorrow.
Created attachment 412448 [details]
Committed r269070: <https://trac.webkit.org/changeset/269070>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 412448 [details].