Add error information to VerifyCertificateChain().

net/cert/internal/verify_certificate_chain.h

Index: net/cert/internal/verify_certificate_chain.h
diff --git a/net/cert/internal/verify_certificate_chain.h b/net/cert/internal/verify_certificate_chain.h
index 6d5c557774c61dba0f0f8656e7bc8b7f06cec5bb..f1d067678fd07f91871239807ceff82ebf72c751 100644
--- a/net/cert/internal/verify_certificate_chain.h
+++ b/net/cert/internal/verify_certificate_chain.h
@@ -10,6 +10,7 @@
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "net/base/net_export.h"
+#include "net/cert/internal/cert_errors.h"
 #include "net/cert/internal/parsed_certificate.h"
 #include "net/der/input.h"
 
@@ -46,7 +47,8 @@ class TrustStore;
 //      * cert_chain[N-1] must be issued by the trust anchor.
 //
 //   trust_anchor:
-//     Contains the trust anchor (root) used to verify the chain.
+//     Contains the trust anchor (root) used to verify the chain. Must be
+//     non-null.
 //
 //   signature_policy:
 //     The policy to use when verifying signatures (what hash algorithms are
@@ -60,11 +62,43 @@ class TrustStore;
 // ---------
 //
 //   Returns true if the target certificate can be verified.
+//
+//   errors:
+//     Must be non-null. The set of errors/warnings encountered while
+//     validating the path are appended to this structure. There is no
+//     guarantee that on success |errors| is empty, or conversely that
+//     on failure |errors| is non-empty. Consumers must only use the
+//     boolean return value to determine success/failure.
 NET_EXPORT bool VerifyCertificateChain(const ParsedCertificateList& certs,
                                        const TrustAnchor* trust_anchor,
                                        const SignaturePolicy* signature_policy,
-                                       const der::GeneralizedTime& time)
-    WARN_UNUSED_RESULT;
+                                       const der::GeneralizedTime& time,
+                                       CertErrors* errors) WARN_UNUSED_RESULT;
+
+// -----------------------------------------------
+// Errors/Warnings set by VerifyCertificateChain
+// -----------------------------------------------
+
+namespace verify_certificate_chain_errors {
+
+// TODO(eroman): Document each of these and their parameters.
+extern CertErrorType kSignatureAlgorithmMismatch;
+extern CertErrorType kInvalidOrUnsupportedAlgorithm;
+extern CertErrorType kChainIsEmpty;
+extern CertErrorType kUnconsumedCriticalExtension;
+extern CertErrorType kTargetCertInconsistentCaBits;
+extern CertErrorType kKeyCertSignBitNotSet;
+extern CertErrorType kMaxPathLengthViolated;
+extern CertErrorType kBasicConstraintsIndicatesNotCa;
+extern CertErrorType kMissingBasicConstraints;
+extern CertErrorType kNotPermitterdByNameConstraints;
+extern CertErrorType kSubjectDoesNotMatchIssuer;
+extern CertErrorType kSignatureVerificationFailed;
+extern CertErrorType kValidityFailedNotAfter;
+extern CertErrorType kValidityFailedNotBefore;
+extern CertErrorType kSignatureAlgorithmsDifferentEncoding;
+
+}  // namespace verify_certificate_chain_errors
 
 }  // namespace net