Add variations header tests for service worker-related requests.

Bug: 901082, 922291
Change-Id: I73fb7e0a5e427fdbbf0089ba2e27bf93f50159dc
Reviewed-on: https://chromium-review.googlesource.com/c/1420508
Commit-Queue: Matt Mueller <mattm@chromium.org>
Reviewed-by: Matt Mueller <mattm@chromium.org>
Auto-Submit: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625066}
5 files changed