Ensure that privates are private.

chrome/renderer/resources/extensions/enterprise_platform_keys/subtle_crypto.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 internalAPI = require('enterprise.platformKeys.internalAPI');
 var intersect = require('platformKeys.utils').intersect;
 var subtleCryptoModule = require('platformKeys.SubtleCrypto');
-var SubtleCrypto = subtleCryptoModule.SubtleCrypto;
 var SubtleCryptoImpl = subtleCryptoModule.SubtleCryptoImpl;
 var KeyPair = require('enterprise.platformKeys.KeyPair').KeyPair;
 var KeyUsage = require('platformKeys.Key').KeyUsage;
 
 var normalizeAlgorithm =
     requireNative('platform_keys_natives').NormalizeAlgorithm;
 
 // This error is thrown by the internal and public API's token functions and
 // must be rethrown by this custom binding. Keep this in sync with the C++ part
 // of this API.
@@ skipping 106 matching lines @@
         return;
       if (chrome.runtime.lastError) {
         reject(CreateOperationError());
         return;
       }
       resolve(new KeyPair(spki, normalizedAlgorithmParameters, keyUsages));
     });
   });
 };
 
-exports.SubtleCrypto =
-    utils.expose('SubtleCrypto',
-                 EnterpriseSubtleCryptoImpl,
-                 {
-                   superclass: SubtleCrypto,
-                   functions: ['generateKey']
-                   // ['sign', 'exportKey'] are exposed by the base class
-                 });
+function SubtleCrypto() {
+  privates(SubtleCrypto).constructPrivate(this, arguments);
+}
+utils.expose(SubtleCrypto, EnterpriseSubtleCryptoImpl, {
+  superclass: subtleCryptoModule.SubtleCrypto,
+  functions: [
+    'generateKey',
+    // 'sign', 'exportKey' are exposed by the base class
+  ],
+});
+
+exports.$set('SubtleCrypto', SubtleCrypto);