Enable ES6 Symbols by default

src/v8natives.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file relies on the fact that the following declarations have been made
 // in runtime.js:
 // var $Object = global.Object;
 // var $Boolean = global.Boolean;
 // var $Number = global.Number;
 // var $Function = global.Function;
@@ skipping 1162 matching lines @@
 
 
 function GetOwnEnumerablePropertyNames(object) {
   var names = new InternalArray();
   for (var key in object) {
     if (%HasOwnProperty(object, key)) {
       names.push(key);
     }
   }
 
-  // FLAG_harmony_symbols may be on, but symbols aren't included by for-in.
   var filter = PROPERTY_ATTRIBUTES_STRING | PROPERTY_ATTRIBUTES_PRIVATE_SYMBOL;
   var symbols = %GetOwnPropertyNames(object, filter);
   for (var i = 0; i < symbols.length; ++i) {
     var symbol = symbols[i];
     if (IS_SYMBOL(symbol)) {
       var desc = ObjectGetOwnPropertyDescriptor(object, symbol);
       if (desc.enumerable) names.push(symbol);
     }
   }
 
@@ skipping 675 matching lines @@
   %SetCode($Function, FunctionConstructor);
   %AddNamedProperty($Function.prototype, "constructor", $Function, DONT_ENUM);
 
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
     "bind", FunctionBind,
     "toString", FunctionToString
   ));
 }
 
 SetUpFunction();