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This CL introduces a new protobuf to store encrypted
CertLoggerRequests. Serialized certificate reports are encrypted with an
AES-CTR-128-HMAC-SHA256 AEAD (from BoringSSL, thus encrypted reports are
only supported on BoringSSL platforms) before being uploaded to HTTP
endpoints. |CertificateErrorReporter::IsHttpUploadUrlSupported| allows
users of the class to set an HTTP URL if supported.

BUG=461590

Review URL: https://codereview.chromium.org/1083493003

Cr-Commit-Position: refs/heads/master@{#326876}