Update from https://crrev.com/303153

net/base/keygen_handler_win.cc

 // Copyright (c) 2011 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/base/keygen_handler.h"
 
 #include <windows.h>
 #include <rpc.h>
 
 #include <list>
@@ skipping 47 matching lines @@
   return true;
 }
 
 // Generates a DER encoded SignedPublicKeyAndChallenge structure from the
 // signing key of |prov| and the specified ASCII |challenge| string and
 // appends it to |output|.
 // True if the encoding was successfully generated.
 bool GetSignedPublicKeyAndChallenge(HCRYPTPROV prov,
                                     const std::string& challenge,
                                     std::string* output) {
-  std::wstring wide_challenge = base::ASCIIToWide(challenge);
+  base::string16 challenge16 = base::ASCIIToUTF16(challenge);
   std::vector<BYTE> spki;
 
   if (!GetSubjectPublicKeyInfo(prov, &spki))
     return false;
 
   // PublicKeyAndChallenge ::= SEQUENCE {
   //     spki SubjectPublicKeyInfo,
   //     challenge IA5STRING
   // }
   CERT_KEYGEN_REQUEST_INFO pkac;
   pkac.dwVersion = CERT_KEYGEN_REQUEST_V1;
   pkac.SubjectPublicKeyInfo =
       *reinterpret_cast<PCERT_PUBLIC_KEY_INFO>(&spki[0]);
-  pkac.pwszChallengeString = const_cast<wchar_t*>(wide_challenge.c_str());
+  pkac.pwszChallengeString = const_cast<base::char16*>(challenge16.c_str());
 
   CRYPT_ALGORITHM_IDENTIFIER sig_alg;
   memset(&sig_alg, 0, sizeof(sig_alg));
   sig_alg.pszObjId = const_cast<char*>(szOID_RSA_MD5RSA);
 
   BOOL ok;
   DWORD size = 0;
   std::vector<BYTE> signed_pkac;
   ok = CryptSignAndEncodeCertificate(prov, AT_KEYEXCHANGE, X509_ASN_ENCODING,
                                      X509_KEYGEN_REQUEST_TO_BE_SIGNED,
@@ skipping 120 matching lines @@
 
     std::string result;
     base::Base64Encode(spkac, &result);
 
     VLOG(1) << "Keygen succeeded";
     return result;
   }
 }
 
 }  // namespace net