Fix -Wsign-compare warning after https://codereview.chromium.org/1557133002

net/cert/cert_verify_proc_win.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/cert_verify_proc_win.h"
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 786 matching lines @@
         // zero. Thus NOT having the bit set is equivalent to having found a
         // matching certificate.
         if (!(store_search_flags & CERT_STORE_SIGNATURE_FLAG)) {
           // No need to dupe; reference is held.
           issuer_cert.reset(previous_cert);
           break;
         }
       }
       if (issuer_cert)
         break;
-      if (GetLastError() == CRYPT_E_SELF_SIGNED) {
+      if (GetLastError() == static_cast<DWORD>(CRYPT_E_SELF_SIGNED)) {
         issuer_cert.reset(CertDuplicateCertificateContext(subject_cert));
         break;
       }
     }
 
     // At this point, the Microsoft provider opens up the "CA", "Root", and
     // "SPC" stores to search for the issuer certificate, if not found in the
     // caller-supplied stores. It is unclear whether that is necessary here.
   }
 
@@ skipping 326 matching lines @@
     return MapCertStatusToNetError(verify_result->cert_status);
 
   if (ev_policy_oid &&
       CheckEV(chain_context, rev_checking_enabled, ev_policy_oid)) {
     verify_result->cert_status |= CERT_STATUS_IS_EV;
   }
   return OK;
 }
 
 }  // namespace net