Finalize implementation of policy_ProxySettings test.

This test verifies the behavior of Chrome OS for a limited range of
valid configurations of the ProxySettings user policy.

BUG=chromium:528504
TEST=Run test_that <IP> policy_ProxySettings

Change-Id: Id99a918e79ce74b7fad4c9bac74f67db5863de3c
Reviewed-on: https://chromium-review.googlesource.com/325301
Commit-Ready: Scott Cunningham <scunningham@chromium.org>
Tested-by: Scott Cunningham <scunningham@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
2 files changed