Detect SHA-1 when it appears in certificate chains

BUG=401365
TBR=davidben

Review URL: https://codereview.chromium.org/509273002

Cr-Commit-Position: refs/heads/master@{#297307}
(cherry picked from commit b92e6f5c2a5271850a39afa1254d41ccc34ec5e6)

Review URL: https://codereview.chromium.org/614353006

Cr-Commit-Position: refs/branch-heads/2171@{#21}
Cr-Branched-From: 267aeeb8d85c8503a7fd12bd14654b8ea78d3974-refs/heads/master@{#297060}
8 files changed