GitLab

Be strict on request's Content-Type by only allowing whitespace
before type and after subtype.

Behavior matches Firefox.

Bug: 902681
Change-Id: Id08c0c56076c5b4aa6e335893f663b7d91229da1
Reviewed-on: https://chromium-review.googlesource.com/c/1341508
Commit-Queue: Rob Buis <rbuis@igalia.com>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609667}