Mac: Fix crash in CreateSecCertificateArrayForX509Certificate.

net/cert/x509_util_mac.cc

Index: net/cert/x509_util_mac.cc
diff --git a/net/cert/x509_util_mac.cc b/net/cert/x509_util_mac.cc
index 0e12a64702a787bb7e754066a3b6d5aaa168da0b..c8f6a2f4a8e0110714e5932a68bacaecda9705c9 100644
--- a/net/cert/x509_util_mac.cc
+++ b/net/cert/x509_util_mac.cc
@@ -111,6 +111,8 @@ CreateSecCertificateArrayForX509Certificate(X509Certificate* cert) {
     base::ScopedCFTypeRef<SecCertificateRef> sec_cert(
         CreateSecCertificateFromBytes(CRYPTO_BUFFER_data(intermediate),
                                       CRYPTO_BUFFER_len(intermediate)));
+    if (!sec_cert)
+      return base::ScopedCFTypeRef<CFMutableArrayRef>();
     CFArrayAppendValue(cert_list, sec_cert);
   }
 #else