Account for the OS returning an empty certificate chain.

net/cert/x509_certificate_mac.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/cert/x509_certificate.h"
 
 #include <CommonCrypto/CommonDigest.h>
 #include <CoreServices/CoreServices.h>
 #include <Security/Security.h>
 
@@ skipping 479 matching lines @@
 void X509Certificate::GetPublicKeyInfo(OSCertHandle cert_handle,
                                        size_t* size_bits,
                                        PublicKeyType* type) {
   // Since we might fail, set the output parameters to default values first.
   *type = kPublicKeyTypeUnknown;
   *size_bits = 0;
 
   SecKeyRef key;
   OSStatus status = SecCertificateCopyPublicKey(cert_handle, &key);
   if (status) {
-    NOTREACHED() << "SecCertificateCopyPublicKey failed: " << status;
+    // SecCertificateCopyPublicKey may fail if the certificate has an invalid
+    // key. See https://crbug.com/472291.
+    LOG(WARNING) << "SecCertificateCopyPublicKey failed: " << status;
     return;
   }
   ScopedCFTypeRef<SecKeyRef> scoped_key(key);
 
   const CSSM_KEY* cssm_key;
   status = SecKeyGetCSSMKey(key, &cssm_key);
   if (status) {
     NOTREACHED() << "SecKeyGetCSSMKey failed: " << status;
     return;
   }
@@ skipping 51 matching lines @@
   status = SecCertificateGetData(cert_handle, &cert_data);
   if (status)
     return false;
 
   if (CSSM_CL_CertVerify(cl_handle, 0, &cert_data, &cert_data, NULL, 0))
     return false;
   return true;
 }
 
 }  // namespace net