GitLab

Allow referring to extension-provided keys/client certificates by
Subject Public Key Info (SPKI).

Bug: 826417, 531351
Test: unit_tests --gtest_filter=CertificateProviderServiceTest*
Change-Id: I0a6ee71e4a2d19957a2d675750cb86afda483eb3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1667345Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Pavol Marko <pmarko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#671563}