There was no difference between these two classes in a hierarchical
relationship.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/532473002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23560 ce2b1a6d-e550-0410-aec6-3dcde31c8c00