GitLab

Previously ConnectionToClient required stubs to be created before the
client is authenticated. This is no longer necessary. Fixed it so
set_*_stub() methods can be called only after authentication. Also
removed auth input filters from ClientSession as they are no longer
useful.

BUG=448838

Review URL: https://codereview.chromium.org/902613004

Cr-Commit-Position: refs/heads/master@{#316299}