Roll src/third_party/boringssl/src afe57cb14..6c22f542f

https://boringssl.googlesource.com/boringssl/+log/afe57cb14d36f70ad4a109fc5e7765d1adc67035..6c22f542f42eccb0de7f43edf27aa1255c7be7e2

As this pulls in a new ECDH curve, add X25519 to histograms.xml. Also fix
OPENSSL_SMALL definition in GYP. direct_dependent_settings doesn't apply to the
current target (oops). It also no longer needs to be exported; no test or
header file depends on it anymore.

BUG=571231

Review URL: https://codereview.chromium.org/1608963004

Cr-Commit-Position: refs/heads/master@{#370617}
23 files changed