This should make it possible to integrate into more tools.

Bug: 1013096
Change-Id: Idd1502996dafc28b1e5b1bf731125bd64c4f5162
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3613833
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>