R=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/209533002

Patch from Kang-Hao (Kenny) Lu <kennyluck@csail.mit.edu>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20193 ce2b1a6d-e550-0410-aec6-3dcde31c8c00