Added options to docgen.py
Added options to docgen.py

Can now clean up the generated files.

BUG=362735

Review URL: https://codereview.chromium.org/629373002

nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra