Allowed parsing reporting endpoints through the `report-to` directive

This patch adds functionality to parse the `report-to` csp directive
It does not actually do any reporting
It does not update the content layer csp version
Spec: https://wicg.github.io/reporting/

Bug: 726634
Change-Id: I31546a56a18504684fc292ce76973ae6fab50fec
Reviewed-on: https://chromium-review.googlesource.com/563210
Commit-Queue: Andy Paicu <andypaicu@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490978}
6 files changed