Add a console control handler chrome_watcher.dll.

This will hopefully allow conclusively answering whether the problem is
at ExitWindows-time.

R=erikwright@chromium.org, mpearson@chromium.org
BUG=412384

Review URL: https://codereview.chromium.org/811603003

Cr-Commit-Position: refs/heads/master@{#309201}
5 files changed