Reland "Portals: Restrict portal navigations to HTTP family."

This is a reland of 69ec73d0fabce5b339b0b125fc60f6722e7e958d

Original change's description:
> Portals: Restrict portal navigations to HTTP family.
> 
> This is also enforced with a renderer kill in case the browser receives
> a non-HTTP navigation request.
> 
> Bug: 962500
> Change-Id: Id7c122ba80ef1cc00620d07d5ecdb1f268b04d79
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1615499
> Commit-Queue: Lucas Gadani <lfg@chromium.org>
> Reviewed-by: Charlie Reis <creis@chromium.org>
> Reviewed-by: Jeremy Roman <jbroman@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#660918}

Bug: 962500
Change-Id: I562cfa21b527e134d7e8e1fed4bab55a05d3d2a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1621871
Commit-Queue: Charlie Reis <creis@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661985}
3 files changed