Introduce blink::WebCanonicalCookie

Add a blink analogue for net::CanonicalCookie. This is initially
used by the CookieStore. Once the RestrictedCookieManager is ready,
Document cookie/setCookie can be changed to it directly instead of
a parallel pipeline to the browser with redundant security checks.
A mojo type mapping is introduced. net::CanonicalCookie is not used
directly due to std::string vs. WTF::String uncertainty, but we may
revisit this in the future.

Bug: 729800
Change-Id: I1492379bee98d44f13470e32da794616b905260b
Reviewed-on: https://chromium-review.googlesource.com/1062599
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566588}
14 files changed