size of the change, the initial implementation provides read access to
the frame (eg, locals, parameters, and expression stack elements) but
no mutation.
Review URL: http://codereview.chromium.org/7302

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@694 ce2b1a6d-e550-0410-aec6-3dcde31c8c00