E.g. tools_webrtc/libs/generate_licenses_test.py needs 'mock', which needs the other libs added here.
This is taken from 641bce4223/.vpython (29)
TBR: kwiberg@webrtc.org
No-Try: True
Bug: chromium:749664
Change-Id: I180fc1190d2664c5a82f63857b740334145e7daa
Reviewed-on: https://webrtc-review.googlesource.com/77520
Commit-Queue: Oleh Prypin <oprypin@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23294}