Port r12686 (bdda5c81)

BUG=
TEST=

Review URL: https://codereview.chromium.org/11143029
Patch from Akos Palfi <palfia@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12738 ce2b1a6d-e550-0410-aec6-3dcde31c8c00