Comment 3 for bug 1797446

I think we can split apart the bits in KSM to have "process environment" and "get environment data". If we do this split, keystone can use the "process environment" code and supply the environment directly from flask.request.environ instead of assuming the data will come from a webob request object. This means that keystone benefits from all the work KSM does, but can push AuthContext down to a simple "pre-request" function that populates the sane bits of the environment used further down the stack.