The call sites are more concise, the naming is better and at least one
case of superfluous code in release mode was removed.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/11108011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12712 ce2b1a6d-e550-0410-aec6-3dcde31c8c00