Handlify BasicJsonStringifier.

R=ishell@chromium.org

Review URL: https://codereview.chromium.org/238273005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20768 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Use a wrapper for copying object.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/238113003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20769 ce2b1a6d-e550-0410-aec6-3dcde31c8c00