Switch to standard integer types in components/, part 2 of 4.

components/gcm_driver/crypto/p256_key_util_openssl.cc

 // Copyright 2015 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 "components/gcm_driver/crypto/p256_key_util.h"
 
+#include <stddef.h>
 #include <stdint.h>
 
 #include <openssl/ec.h>
 #include <openssl/ecdh.h>
 #include <openssl/evp.h>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_util.h"
 #include "crypto/ec_private_key.h"
@@ skipping 53 matching lines @@
                        ec_private_key.get(), nullptr) != sizeof(result)) {
     DLOG(ERROR) << "Unable to compute the ECDH shared secret.";
     return false;
   }
 
   out_shared_secret->assign(reinterpret_cast<char*>(result), sizeof(result));
   return true;
 }
 
 }  // namespace gcm