R=benm@chromium.org, ulan@chromium.org, torne@chromium.org

TEST=manual
BUG=

Review URL: https://codereview.chromium.org/598723002

Patch from Dehao Chen <dehao@google.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24219 ce2b1a6d-e550-0410-aec6-3dcde31c8c00