For writing modes: horizontal-bt/vertical-rl, the content overflowing last region is improperly displayed.
Created attachment 180984 [details] Patch
Created attachment 181171 [details] Patch 2 Modified also hit testing to take these writing modes into account when computing the region clipping rect.
Comment on attachment 181171 [details] Patch 2 r=me
Created attachment 181284 [details] Patch for landing
Comment on attachment 181284 [details] Patch for landing Clearing flags on attachment: 181284 Committed r138785: <http://trac.webkit.org/changeset/138785>
All reviewed patches have been landed. Closing bug.