Ensure that privates are private.

chrome/renderer/resources/extensions/enterprise_platform_keys/key_pair.js

 // Copyright 2014 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.
 
 var utils = require('utils');
 var intersect = require('platformKeys.utils').intersect;
 var keyModule = require('platformKeys.Key');
 var Key = keyModule.Key;
 var KeyType = keyModule.KeyType;
 var KeyUsage = keyModule.KeyUsage;
@@ skipping 12 matching lines @@
                            algorithm,
                            intersect([KeyUsage.verify], usages),
                            true /* extractable */);
   this.privateKey = new Key(KeyType.private,
                             publicKeySpki,
                             algorithm,
                             intersect([KeyUsage.sign], usages),
                             false /* not extractable */);
 };
 
-exports.KeyPair = utils.expose('KeyPair',
-                               KeyPairImpl,
-                               {readonly:['publicKey', 'privateKey']});
+function KeyPair() {
+  privates(KeyPair).constructPrivate(this, arguments);
+}
+utils.expose(KeyPair, KeyPairImpl, {
+  readonly: [
+    'publicKey',
+    'privateKey',
+  ],
+});
+
+exports.$set('KeyPair', KeyPair);