[Extensions] Finish freezing schema

extensions/renderer/resources/event.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 exceptionHandler = require('uncaught_exception_handler');
   var eventNatives = requireNative('event_natives');
   var logging = requireNative('logging');
   var schemaRegistry = requireNative('schema_registry');
   var sendRequest = require('sendRequest').sendRequest;
   var utils = require('utils');
@@ skipping 121 matching lines @@
 
   function parseEventOptions(opt_eventOptions) {
     function merge(dest, src) {
       for (var k in src) {
         if (!$Object.hasOwnProperty(dest, k)) {
           dest[k] = src[k];
         }
       }
     }
 
-    var options = opt_eventOptions || {};
+    var options = $Object.assign({}, opt_eventOptions || {});
     merge(options, {
       // Event supports adding listeners with filters ("filtered events"), for
       // example as used in the webNavigation API.
       //
       // event.addListener(listener, [filter1, filter2]);
       supportsFilters: false,
 
       // Events supports vanilla events. Most APIs use these.
       //
       // event.addListener(listener);
@@ skipping 348 matching lines @@
     'removeRules',
     'getRules'
   ] });
 
   // NOTE: Event is (lazily) exposed as chrome.Event from dispatcher.cc.
   exports.$set('Event', Event);
 
   exports.$set('dispatchEvent', dispatchEvent);
   exports.$set('parseEventOptions', parseEventOptions);
   exports.$set('registerArgumentMassager', registerArgumentMassager);