This might be a big win in a browser setting where a lot of string
conversions can be avoided.  On the other hand it adds extra pressure
on the global handle system.
Review URL: http://codereview.chromium.org/11404

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@772 ce2b1a6d-e550-0410-aec6-3dcde31c8c00