This was introduced by https://code.google.com/p/v8/source/detail?r=20857

R=adamk@chromium.org
TBR=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/241433002

Patch from Erik Arvidsson <arv@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20858 ce2b1a6d-e550-0410-aec6-3dcde31c8c00