Switch //net/ntlm to use base::span<const uint8_t>

//net/ntlm makes extensive use of uint8_t* pointers with various
fixed size requirements. Convert these into defined-extent
base::span<>'s so that the compiler can do more work for us to
ensure that all the buffers are appropriately sized.

This also switches uses of std::basic_string<uint8_t> and
base::StringPiece into std::vector<uint8_t> / base::span<uint8_t>,
as these are all working on 'data' buffers.

Bug: 837308
Change-Id: Iae3f1933b2c948d77c841e6f9bc8ce04bfddc67d
Reviewed-on: https://chromium-review.googlesource.com/1056013
Commit-Queue: Ryan Sleevi <rsleevi@chromium.org>
Reviewed-by: Asanka Herath <asanka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558579}
21 files changed