It depends on dev-python/pbr, pulling in.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/portage-stable/+/b5d93194e2c92340906245547421b9402c711f74

commit b5d93194e2c92340906245547421b9402c711f74
Author: Dean Liao <deanliao@chromium.org>
Date: Mon Dec 11 20:47:48 2017

mock: upgraded package to upstream

Upgraded dev-python/mock to version 2.0.0 on amd64, arm, x86

The commit is generated by:
cros_portage_upgrade --upgrade --board=amd64-generic:arm-generic:x86-generic \
                     --local-only dev-python/mock
where I manually changed EAPI from 6 to 5 in
/tmp/portage/dev-python/mock/mock-2.0.0.ebuild
before running cros_portage_upgrade to upgrade to mock-2.0.0.

BUG= chromium:789388 
TEST=Trybot

Change-Id: Ie9ba39e90344abc2bbae3c76f71348891daa6479
Reviewed-on: https://chromium-review.googlesource.com/813556
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Shuo-Peng Liao <deanliao@chromium.org>
Reviewed-by: Chung-yih Wang <cywang@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[delete] https://crrev.com/1a8b7c29446ebc4215e5e51cde6d4c0a1b8af407/metadata/md5-cache/dev-python/mock-1.0.1
[add] https://crrev.com/b5d93194e2c92340906245547421b9402c711f74/metadata/md5-cache/dev-python/mock-2.0.0
[add] https://crrev.com/b5d93194e2c92340906245547421b9402c711f74/dev-python/mock/mock-2.0.0.ebuild
[modify] https://crrev.com/b5d93194e2c92340906245547421b9402c711f74/dev-python/mock/metadata.xml
[modify] https://crrev.com/b5d93194e2c92340906245547421b9402c711f74/dev-python/mock/Manifest
[delete] https://crrev.com/1a8b7c29446ebc4215e5e51cde6d4c0a1b8af407/dev-python/mock/mock-1.0.1.ebuild