GitLab

Relanding https://chromium-review.googlesource.com/c/1449151 with fixes.

Patchset 1 is https://chromium-review.googlesource.com/c/1449151

Patchset 2 is https://chromium-review.googlesource.com/c/1464228

Patchset 3 is the new fix. When you run a telemetry benchmark as a
reference, you are supposed to do
`run_benchmark benchmark_name --browser=reference`
but I thought that you were supposed to do
`run_benchmark benchmark_name.reference --browser=reference`
because I read the earlier code wrong.
I also added a end to end test for this behavior, which also
covers sharding code as well.

Patchset 5 is a unittest for
https://chromium-review.googlesource.com/c/1464228

Bug: 930879, 928928, 927507, 923628, 920002, 744736
Change-Id: If73d929b8e1b32c33d2bed7d2298b64d205658c1
Reviewed-on: https://chromium-review.googlesource.com/c/1467907Reviewed-by: Emily Hanley <eyaich@chromium.org>
Reviewed-by: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632333}