The implementation is not yet complete, it doesn't support blocking yet,
and doesn't collect statistics.

This things will be fixed in follow-up CLs.

BUG=v8:3608
R=yangguo@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/620093003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24425 ce2b1a6d-e550-0410-aec6-3dcde31c8c00