Native context: do not put public symbols and flags on the js builtins object.

src/debug/mirrors.js

 // Copyright 2006-2012 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.
 
 (function(global, utils) {
 "use strict";
 
 // ----------------------------------------------------------------------------
 // Imports
 
 var FunctionSourceString;
 var GlobalArray = global.Array;
 var IsNaN = global.isNaN;
 var JSONStringify = global.JSON.stringify;
 var MathMin = global.Math.min;
-var promiseStatusSymbol = utils.GetPrivateSymbol("promise_status_symbol");
-var promiseValueSymbol = utils.GetPrivateSymbol("promise_value_symbol");
+var promiseStatusSymbol = utils.ImportNow("promise_status_symbol");
+var promiseValueSymbol = utils.ImportNow("promise_value_symbol");
+var SymbolToString;
 var ToBoolean;
 var ToString;
 
 utils.Import(function(from) {
   FunctionSourceString = from.FunctionSourceString;
+  SymbolToString = from.SymbolToString;
   ToBoolean = from.ToBoolean;
   ToString = from.ToString;
 });
 
 // ----------------------------------------------------------------------------
 
 // Mirror hierarchy:
 // - Mirror
 //   - ValueMirror
 //     - UndefinedMirror
@@ skipping 654 matching lines @@
 }
 inherits(SymbolMirror, ValueMirror);
 
 
 SymbolMirror.prototype.description = function() {
   return %SymbolDescription(%_ValueOf(this.value_));
 }
 
 
 SymbolMirror.prototype.toText = function() {
-  return %_CallFunction(this.value_, builtins.$symbolToString);
+  return %_CallFunction(this.value_, SymbolToString);
 }
 
 
 /**
  * Mirror object for objects.
  * @param {object} value The object reflected by this mirror
  * @param {boolean} transient indicate whether this object is transient with a
  *    transient handle
  * @constructor
  * @extends ValueMirror
@@ skipping 2401 matching lines @@
 // Functions needed by the debugger runtime.
 utils.InstallFunctions(utils, DONT_ENUM, [
   "ClearMirrorCache", ClearMirrorCache
 ]);
 
 // Export to debug.js
 utils.Export(function(to) {
   to.MirrorType = MirrorType;
 });
 })