Do not overwrite Object.freeze

Summary: Now that React Native ships with a newer version of JSC, we do not need this code to wrap `Object.freeze` any longer.

Reviewed By: mmmulani

Differential Revision: D14779239

fbshipit-source-id: 1a6e1a9c7f4312572bd08ba604fa8c9d6b1927e1

Libraries/Core/__tests__/MapAndSetPolyfills-test.js

@@ -14,8 +14,6 @@ const {freeze, seal, preventExtensions} = Object;
 
 function setup() {
   jest.setMock('../../vendor/core/_shouldPolyfillES6Collection', () => true);
-  jest.unmock('_wrapObjectFreezeAndFriends');
-  require('_wrapObjectFreezeAndFriends');
 }
 
 function cleanup() {

Libraries/Core/polyfillES6Collections.js

@@ -18,10 +18,8 @@ const {polyfillGlobal} = require('PolyfillFunctions');
  */
 const _shouldPolyfillCollection = require('_shouldPolyfillES6Collection');
 if (_shouldPolyfillCollection('Map')) {
-  require('_wrapObjectFreezeAndFriends');
   polyfillGlobal('Map', () => require('Map'));
 }
 if (_shouldPolyfillCollection('Set')) {
-  require('_wrapObjectFreezeAndFriends');
   polyfillGlobal('Set', () => require('Set'));
 }

Libraries/vendor/core/Map.js

@@ -26,9 +26,6 @@ module.exports = (function(global, undefined) {
     return global.Map;
   }
 
-  // In case this module has not already been evaluated, import it now.
-  require('./_wrapObjectFreezeAndFriends');
-
   const hasOwn = Object.prototype.hasOwnProperty;
 
   /**

Libraries/vendor/core/_wrapObjectFreezeAndFriends.js

@@ -1,39 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @author Ben Newman (@benjamn) <ben@benjamn.com>
- * @flow
- * @format
- */
-
-'use strict';
-
-let testMap; // Initialized lazily.
-function getTestMap() {
-  return testMap || (testMap = new (require('./Map'))());
-}
-
-// Wrap Object.{freeze,seal,preventExtensions} so each function adds its
-// argument to a Map first, which gives our ./Map.js polyfill a chance to
-// tag the object before it becomes non-extensible.
-['freeze', 'seal', 'preventExtensions'].forEach(name => {
-  const method = Object[name];
-  if (typeof method === 'function') {
-    (Object: any)[name] = function(obj) {
-      try {
-        // If .set succeeds, also call .delete to avoid leaking memory.
-        getTestMap()
-          .set(obj, obj)
-          .delete(obj);
-      } finally {
-        // If .set fails, the exception will be silently swallowed
-        // by this return-from-finally statement, and the method will
-        // behave exactly as it did before it was wrapped.
-        return method.call(Object, obj);
-      }
-    };
-  }
-});