GitLab

When we added support for versioned message we accidentally introduced a
behavior where messages can be shorter than expected. This is what the
behavior should be to allow older messages to be received. However,
we know the minimum size is the oldest message version. We should
never be allowed to go smaller than that.

This second attempt will explicitly shutdown the channel in the test to
avoid a UAF on Mac.

BUG=chromium:1149805

Change-Id: I0a1daaf69db7ca74963803f8a92c31bfea3aa0df
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2547479
Auto-Submit: Brian Geffon <bgeffon@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Brian Geffon <bgeffon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828922}