Skeleton for the Async Cookies API.

This is a skeleton for the browser-side, renderer-side, and Mojo implementation
of the Async Cookies API.

In the interest of keeping the CL readable, the skeleton does not
include difficult details such as security checks and thorough option
parsing. The CL also doesn't implement the "easy" methods that can be
written on top of CookieStore.getAll and CookieStore.set. Once this Mojo
skeleton is landed, follow-up CLs will fill these gaps and add test
coverage using WPT-style layout tests.

Bug: 729800
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_site_isolation
Change-Id: I4328d9b92422d6d10f04ebe72e6461a71969a857
Reviewed-on: https://chromium-review.googlesource.com/602673
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Randy Smith <rdsmith@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508508}
33 files changed