Check X509Certificate::CreateFromHandle result.

net/cert/cert_verify_proc_builtin.cc

 // Copyright (c) 2017 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/cert_verify_proc_builtin.h"
 
 #include <string>
 #include <vector>
 
 #if defined(USE_NSS_CERTS)
@@ skipping 291 matching lines @@
     intermediates.push_back(CreateOSCertHandle(path.path.certs[i]));
 
   if (path.path.trust_anchor) {
     // TODO(eroman): This assumes that TrustAnchor::cert() cannot be null,
     //               which disagrees with the documentation.
     intermediates.push_back(CreateOSCertHandle(path.path.trust_anchor->cert()));
   }
 
   scoped_refptr<X509Certificate> result = X509Certificate::CreateFromHandle(
       target_cert->os_cert_handle(), intermediates);
+  // |target_cert| was already successfully parsed, so this should never fail.
+  DCHECK(result);
 
   for (const X509Certificate::OSCertHandle handle : intermediates)
     X509Certificate::FreeOSCertHandle(handle);
 
   return result;
 }
 
 // TODO(crbug.com/649017): Make use of |flags|, |crl_set|, and |ocsp_response|.
 // Also handle key usages, policies and EV.
 //
@@ skipping 105 matching lines @@
              : OK;
 }
 
 }  // namespace
 
 scoped_refptr<CertVerifyProc> CreateCertVerifyProcBuiltin() {
   return scoped_refptr<CertVerifyProc>(new CertVerifyProcBuiltin());
 }
 
 }  // namespace net