[iOS] Use a persistent cookie store for Safe Browsing

This makes SafeBrowsingService use a persistent cookie store,
and clears this cookie store whenever cookies are cleared for
"all time". This makes the behavior on iOS consistent with
the behavior of Safe Browsing on other platforms.

Change-Id: I37fec41b6929386ecf2ce1e29fdbb8e95ac89383
Bug: 1103219
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2291694
Commit-Queue: Ali Juma <ajuma@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#796057}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 6503bbcbca1f1455df3d4a3924f95c3b380ba67f
10 files changed