[net/http auth] Support channel bindings for HTTP authentication.

Start using tls-server-end-point channel bindings for HTTP
authentication if a certificate is available. The current implementation
should work on Windows and Posix. Currently only SHA-256, SHA-384, and
SHA-512 are supported for generating channel bindings.

BUG=270219
R=rsleevi@chromium.org,davidben@chromium.org

Review URL: https://codereview.chromium.org/1408433006

Cr-Commit-Position: refs/heads/master@{#382858}
47 files changed