Revert of [Extensions] Finish freezing schema

chrome/renderer/resources/extensions/chrome_setting.js

 // Copyright (c) 2012 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 Event = require('event_bindings').Event;
 var sendRequest = require('sendRequest').sendRequest;
 var validate = require('schemaUtils').validate;
 
 function extendSchema(schema) {
   var extendedSchema = $Array.slice(schema);
-  $Array.unshift(extendedSchema, {'type': 'string'});
+  extendedSchema.unshift({'type': 'string'});
   return extendedSchema;
 }
 
-// TODO(devlin): Maybe find a way to combine this and ContentSetting.
 function ChromeSetting(prefKey, valueSchema) {
   this.get = function(details, callback) {
     var getSchema = this.functionSchemas.get.definition.parameters;
     validate([details, callback], getSchema);
     return sendRequest('types.ChromeSetting.get',
                        [prefKey, details, callback],
                        extendSchema(getSchema));
   };
   this.set = function(details, callback) {
-    // The set schema included in the Schema object is generic, since it varies
-    // per-setting. However, this is only ever for a single setting, so we can
-    // enforce the types more thoroughly.
-    var rawSetSchema = this.functionSchemas.set.definition.parameters;
-    var rawSettingParam = rawSetSchema[0];
-    var props = $Object.assign({}, rawSettingParam.properties);
-    props.value = valueSchema;
-    var modSettingParam = {
-      name: rawSettingParam.name,
-      type: rawSettingParam.type,
-      properties: props,
-    };
-    var modSetSchema = $Array.slice(rawSetSchema);
-    modSetSchema[0] = modSettingParam;
-    validate([details, callback], modSetSchema);
+    var setSchema = $Array.slice(
+        this.functionSchemas.set.definition.parameters);
+    setSchema[0].properties.value = valueSchema;
+    validate([details, callback], setSchema);
     return sendRequest('types.ChromeSetting.set',
                        [prefKey, details, callback],
-                       extendSchema(modSetSchema));
+                       extendSchema(setSchema));
   };
   this.clear = function(details, callback) {
     var clearSchema = this.functionSchemas.clear.definition.parameters;
     validate([details, callback], clearSchema);
     return sendRequest('types.ChromeSetting.clear',
                        [prefKey, details, callback],
                        extendSchema(clearSchema));
   };
   this.onChange = new Event('types.ChromeSetting.' + prefKey + '.onChange');
 };
 
 exports.$set('ChromeSetting', ChromeSetting);