Don't leak the WatcherThreadManager background thread.
Leaking it triggered some canary/dev build checks on Windows that ensure we don't leak handles. In this case, the leak is ok, but the simplest thing for now is to stop leaking it. A side-benefit is we ensure that Mojo message loops shut down correctly at process shutdown.
BUG=559238
R=sky@chromium.org
Review URL: https://codereview.chromium.org/1471123002 .
Cr-Commit-Position: refs/heads/master@{#361264}
CrOS-Libchrome-Original-Commit: a6342a90e9cac7236600ccf63d6ab586d3debfc4
5 files changed