Add arv to WATCHLISTS for bindings and web_idl

BUG=None
TBR=eseidel@chromium.org

Review URL: https://codereview.chromium.org/54123004

git-svn-id: svn://svn.chromium.org/blink/trunk@161063 bbb929c8-8fbe-4397-9dbb-9b2b20218538