[signin] OAuthMultiloginResult parses SameSite cookie attribute

The SameSite attribute for OAuthMultilogin cookies was hardcoded to
NO_RESTRICTION. This CL reads the attribute from the server response instead.

This CL also improves the unittest by improving coverage for isSecure and
isHttpOnly.

Bug: 965509
Change-Id: If7f397ff3c1ef7a8ebd0942ffb1a1c8654422b6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1626863
Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Commit-Queue: Alex Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#670845}
2 files changed