enterprise.platformKeys: Copy-on-read the 'algorithm' member of Key objects.

chrome/renderer/resources/extensions/enterprise_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}
  */
@@ skipping 22 matching lines @@
  * @constructor
  */
 var KeyImpl = function(type, publicKeySpki, algorithm, usages, extractable) {
   this.type = type;
   this.spki = publicKeySpki;
   this.algorithm = algorithm;
   this.usages = usages;
   this.extractable = extractable;
 };
 
-var Key =
-    utils.expose('Key',
-                 KeyImpl,
-                 {readonly:['extractable', 'type', 'algorithm', 'usages']});
+var KeyBase = function() {};
+
+Object.defineProperty(KeyBase.prototype, 'algorithm', {
+  enumerable: true,
+  get: function() {
+    return utils.deepCopy(privates(this).impl.algorithm);
+  }
+});
+
+var Key = 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.Key = Key;
 exports.KeyType = KeyType;
 exports.KeyUsage = KeyUsage;
 exports.getSpki = getSpki;