cidb: Archive branch field.

CQ-DEPEND=CL:1258629
BUG=chromium:891633
TEST=bin/run_tests

Change-Id: Iaa2991059f5e1a1b538526dfbd2f7ce7d0d6e4be
Reviewed-on: https://chromium-review.googlesource.com/1258882
Commit-Ready: Shuhei Takahashi <nya@chromium.org>
Tested-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
3 files changed