[es6] Fix missing bits for full @@toPrimitive support.

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.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
 //     - NullMirror
 //     - BooleanMirror
@@ skipping 1130 matching lines @@
 };
 
 
 ArrayMirror.prototype.indexedPropertiesFromRange = function(opt_from_index,
                                                             opt_to_index) {
   var from_index = opt_from_index || 0;
   var to_index = opt_to_index || this.length() - 1;
   if (from_index > to_index) return new GlobalArray();
   var values = new GlobalArray(to_index - from_index + 1);
   for (var i = from_index; i <= to_index; i++) {
-    var details = %DebugGetPropertyDetails(this.value_, ToString(i));
+    var details = %DebugGetPropertyDetails(this.value_, TO_STRING(i));
     var value;
     if (details) {
       value = new PropertyMirror(this, i, details);
     } else {
       value = GetUndefinedMirror();
     }
     values[i - from_index] = value;
   }
   return values;
 };
@@ skipping 1926 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;
 });
 })