Make the externally connectable browser test clobber all of the builtins,

chrome/renderer/resources/extensions/utils.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 schemaRegistry = requireNative('schema_registry');
 var CHECK = requireNative('logging').CHECK;
 var WARNING = requireNative('logging').WARNING;
 
 // An object forEach. Calls |f| with each (key, value) pair of |obj|, using
 // |self| as the target.
@@ skipping 14 matching lines @@
     return undefined;
   } else if (matches.length == 1) {
     return matches[0]
   } else {
     throw new Error("Failed lookup of field '" + field + "' with value '" +
                     value + "'");
   }
 }
 
 function loadTypeSchema(typeName, defaultSchema) {
-  var parts = typeName.split('.');
+  var parts = $String.split(typeName, '.');
   if (parts.length == 1) {
     if (defaultSchema == null) {
       WARNING('Trying to reference "' + typeName + '" ' +
               'with neither namespace nor default schema.');
       return null;
     }
     var types = defaultSchema.types;
   } else {
-    var schemaName = parts.slice(0, parts.length - 1).join('.')
+    var schemaName = $Array.join($Array.slice(parts, 0, parts.length - 1), '.');
     var types = schemaRegistry.GetSchema(schemaName).types;
   }
   for (var i = 0; i < types.length; ++i) {
     if (types[i].id == typeName)
       return types[i];
   }
   return null;
 }
 
 exports.forEach = forEach;
 exports.loadTypeSchema = loadTypeSchema;
 exports.lookup = lookup;