Implement crypto signature verification routines using OpenSSL.

extensions/common/api/cast_channel/logging.proto

Index: extensions/common/api/cast_channel/logging.proto
diff --git a/extensions/common/api/cast_channel/logging.proto b/extensions/common/api/cast_channel/logging.proto
index 58d86ac68aa4bec471bb8f0d0b73e81f8798b166..94b2d8afb0405c7caa63a5894306d5e465e73fa1 100644
--- a/extensions/common/api/cast_channel/logging.proto
+++ b/extensions/common/api/cast_channel/logging.proto
@@ -101,10 +101,15 @@ enum ChallengeReplyErrorType {
   CHALLENGE_REPLY_ERROR_MESSAGE_ERROR = 6;
   CHALLENGE_REPLY_ERROR_NO_RESPONSE = 7;
   CHALLENGE_REPLY_ERROR_FINGERPRINT_NOT_FOUND = 8;
-  CHALLENGE_REPLY_ERROR_NSS_CERT_PARSING_FAILED = 9;
-  CHALLENGE_REPLY_ERROR_NSS_CERT_NOT_SIGNED_BY_TRUSTED_CA = 10;
-  CHALLENGE_REPLY_ERROR_NSS_CANNOT_EXTRACT_PUBLIC_KEY = 11;
-  CHALLENGE_REPLY_ERROR_NSS_SIGNED_BLOBS_MISMATCH = 12;
+  CHALLENGE_REPLY_ERROR_CERT_PARSING_FAILED = 9;
+  CHALLENGE_REPLY_ERROR_CERT_NOT_SIGNED_BY_TRUSTED_CA = 10;
+  CHALLENGE_REPLY_ERROR_CANNOT_EXTRACT_PUBLIC_KEY = 11;
+  CHALLENGE_REPLY_ERROR_SIGNED_BLOBS_MISMATCH = 12;
+}
+
+message OpenSSLError {
+  optional string filename = 1;
+  optional int32 line = 2;
 }
 
 message SocketEvent {
@@ -126,6 +131,8 @@ message SocketEvent {
 
   optional ChallengeReplyErrorType challenge_reply_error_type = 11;
   optional int32 nss_error_code = 12;
+
+  repeated OpenSSLError openssl_error = 13;
 }
 
 message AggregatedSocketEvent {