Sanitize inheritance in callers of utils.expose

chrome/renderer/resources/extensions/platform_keys/key.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');
 
 /**
  * Enum of possible key types (subset of WebCrypto.KeyType).
  * @enum {string}
  */
 var KeyType = {
+  __proto__: null,
   public: 'public',
   private: 'private'
 };
 
 /**
  * Enum of possible key usages (subset of WebCrypto.KeyUsage).
  * @enum {string}
  */
 var KeyUsage = {
+  __proto__: null,
   sign: 'sign',
   verify: 'verify'
 };
 
 /**
  * Implementation of WebCrypto.Key used in enterprise.platformKeys.
+ *
  * @param {KeyType} type The type of the new key.
  * @param {ArrayBuffer} publicKeySpki The Subject Public Key Info in DER
  *   encoding.
  * @param {KeyAlgorithm} algorithm The algorithm identifier.
  * @param {KeyUsage[]} usages The allowed key usages.
  * @param {boolean} extractable Whether the key is extractable.
  * @constructor
  */
-var KeyImpl = function(type, publicKeySpki, algorithm, usages, extractable) {
+function KeyImpl(type, publicKeySpki, algorithm, usages, extractable) {
   this.type = type;
   this.spki = publicKeySpki;
   this.algorithm = algorithm;
   this.usages = usages;
   this.extractable = extractable;
+}
+$Object.setPrototypeOf(KeyImpl, null);
+$Object.setPrototypeOf(KeyImpl.prototype, null);
+
+/**
+ * The public base class of Key.
+ */
+function KeyBase() {

[Devlin, 2016/04/26 22:41:25]

nit: let's do "function KeyBase() {}" (one line)

[robwu, 2016/04/26 23:14:33]

Done.

+}
+KeyBase.prototype = {
+  constructor: KeyBase,
+  get algorithm() {
+    return utils.deepCopy(privates(this).impl.algorithm);
+  },
 };
 
-var KeyBase = function() {};
-
-Object.defineProperty(KeyBase.prototype, 'algorithm', {
-  enumerable: true,
-  get: function() {
-    return utils.deepCopy(privates(this).impl.algorithm);
-  }
-});
-
 function Key() {
   privates(Key).constructPrivate(this, arguments);
 }
 utils.expose(Key, KeyImpl, {
   superclass: KeyBase,
   readonly: [
     'extractable',
     'type',
     'usages',
   ],
 });
 
 /**
  * Returns |key|'s Subject Public Key Info. Throws an exception if |key| is not
  * a valid Key object.
+ *
  * @param {Key} key
  * @return {ArrayBuffer} The Subject Public Key Info in DER encoding of |key|.
  */
 function getSpki(key) {
   if (!privates(key))
     throw new Error('Invalid key object.');
   var keyImpl = privates(key).impl;
   if (!keyImpl || !keyImpl.spki)
     throw new Error('Invalid key object.');
   return keyImpl.spki;
 }
 
 exports.$set('Key', Key);
 exports.$set('KeyType', KeyType);
 exports.$set('KeyUsage', KeyUsage);
 exports.$set('getSpki', getSpki);