DevTools: do not expose raw headers for cross-origin requests

Same as https://chromium-review.googlesource.com/c/chromium/src/+/821410/,
but now for the network service.

Bug: 898306, 793692, 721408
Change-Id: I96a2a25e66f4ff528d84baf03d600e4f1c89dd30
Reviewed-on: https://chromium-review.googlesource.com/c/1313739
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Ɓukasz Anforowicz <lukasza@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612685}
18 files changed