Support gtest perf test uploading on LUCI

Adds support for uploading gtest perf test data to the performance
dashboard on LUCI by automatically converting from the gtest JSON
format to histograms when processing the perf results using the
conversion script added in https://crrev.com/c/1377773.

This is necessary because LUCI builders can only upload to the
newer /add_histograms endpoint on the dashboard (which only accepts
histogram data) instead of the older /add_point endpoint (which accepts
ChartJSON/gtest JSON, but only uses IP whitelisting for authentication,
which doesn't work on LUCI).

Also drive-by updates the name used for uploading for the
vr_common_unittests target to keep continuity on the perf dashboard
when uploading using this approach.

Bug: 892303
Change-Id: Ie78e34bdabadce35715b3d4a547e472ceda91a51
Reviewed-on: https://chromium-review.googlesource.com/c/1371008
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620397}
4 files changed