Don't use top/right/bottom/left to describe overflow that is in the block's local coordinate space (which could be flipped). Use minX/maxX/minY/maxY instead.
Created attachment 80943 [details] Patch
Created attachment 80948 [details] Patch
Attachment 80943 [details] did not build on chromium: Build output: http://queues.webkit.org/results/7686882
Fixed in r77397.
Attachment 80948 [details] did not build on chromium: Build output: http://queues.webkit.org/results/7690160