Make V8ValueConverter.FromV8Value behave similarly to JSON.stringify

chrome/renderer/resources/extensions/storage_custom_bindings.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.
 
 // Custom bindings for the storage API.
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 var normalizeArgumentsAndValidate =
     require('schemaUtils').normalizeArgumentsAndValidate
 var sendRequest = require('sendRequest').sendRequest;
@@ skipping 15 matching lines @@
     // callers of registerCustomType().
     var self = this;
     function bindApiFunction(functionName) {
       self[functionName] = function() {
         var funSchema = this.functionSchemas[functionName];
         var args = Array.prototype.slice.call(arguments);
         args = normalizeArgumentsAndValidate(args, funSchema);
         return sendRequest(
             'storage.' + functionName,
             [namespace].concat(args),
-            extendSchema(funSchema.definition.parameters));
+            extendSchema(funSchema.definition.parameters),
+            {preserveNullInObjects: true});
       };
     }
     var apiFunctions = ['get', 'set', 'remove', 'clear', 'getBytesInUse'];
     apiFunctions.forEach(bindApiFunction);
   }
 
   return StorageArea;
 });