GitLab

Chrome internally uses X-Client-Data header, and this should not
triggers CORS preflight request.

TBR=jochen@chromium.org

Bug: 870173, 907018
Change-Id: I67f1711b9065223f9e174e207980940e175031e9
Reviewed-on: https://chromium-review.googlesource.com/c/1335076
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610313}