mozilla/servo — pull request #1363 by ryanhc (2013-12-10 02:33:57+00:00)
Title: removing @ from flowtree. (but cloning boxes when creating a display lis...

Removing all @ from flowtree to make it parallelism-ready.
The connection between displaylist and flowtree is removed, i.e., when displaylist is built, box is cloned.
Whether displaylist still needs to have boxes is a design decision to make.