Remove deprecated Persistent::MakeWeak usage from V8

BUG=none
LOG=n
R=dcarney@chromium.org, ulan@chromium.org

Review URL: https://codereview.chromium.org/101523002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18227 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Use constant types to represent the fixed right arg of a MOD.

R=mvstanton@chromium.org, svenpanne@chromium.org

Review URL: https://codereview.chromium.org/99173002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18228 ce2b1a6d-e550-0410-aec6-3dcde31c8c00