Add chrome_cleaner/ipc dir

Also add missing functions to chrome_cleaner/os needed by IPC unit
tests.

R=proberge

Bug: 830892
Change-Id: Ibc9f4e919264d2e54cbc9808574639abb879b63e
Reviewed-on: https://chromium-review.googlesource.com/1161283
Commit-Queue: Joe Mason <joenotcharles@chromium.org>
Reviewed-by: proberge <proberge@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581555}
26 files changed