Add error information to VerifySignedData().

net/cert/internal/verify_certificate_chain.cc

Index: net/cert/internal/verify_certificate_chain.cc
diff --git a/net/cert/internal/verify_certificate_chain.cc b/net/cert/internal/verify_certificate_chain.cc
index 9dee86a9556cce1ec82e9452d27004765d75ae0b..6d5061337ed38dca1d5220a26691c6f3f335cb21 100644
--- a/net/cert/internal/verify_certificate_chain.cc
+++ b/net/cert/internal/verify_certificate_chain.cc
@@ -160,9 +160,9 @@ WARN_UNUSED_RESULT bool BasicCertificateProcessing(
   }
 
   if (!VerifySignedData(cert.signature_algorithm(), cert.tbs_certificate_tlv(),
-                        cert.signature_value(), working_spki,
-                        signature_policy)) {
-    errors->Add(kSignatureVerificationFailed);
+                        cert.signature_value(), working_spki, signature_policy,
+                        errors)) {
+    errors->Add(kVerifySignedDataFailed);

[eroman, 2016/08/30 21:57:40]

I will explore making errors hiearchical in a follow-up to try and address this
deficiency.

For now the errors is a flat list, and there may be some duplicate entries,
which effectively describe the same issue but at varying levels of granularity.

(Need to circle back on that "scoped" context stuff I had added, and see if that
makes sense as a general mechanism, or if errors should just inherently be
hiearchical and have sub-errors within them).

     return false;
   }
 
@@ -588,8 +588,7 @@ DEFINE_CERT_ERROR_TYPE(kNotPermittedByNameConstraints,
                        "Not permitted by name constraints");
 DEFINE_CERT_ERROR_TYPE(kSubjectDoesNotMatchIssuer,
                        "subject does not match issuer");
-DEFINE_CERT_ERROR_TYPE(kSignatureVerificationFailed,
-                       "Signature verification failed");
+DEFINE_CERT_ERROR_TYPE(kVerifySignedDataFailed, "VerifySignedData failed");
 DEFINE_CERT_ERROR_TYPE(kValidityFailedNotAfter, "Time is after notAfter");
 DEFINE_CERT_ERROR_TYPE(kValidityFailedNotBefore, "Time is before notBefore");
 DEFINE_CERT_ERROR_TYPE(kSignatureAlgorithmsDifferentEncoding,