Hide Symbol implementation in a closure.

src/harmony-array.js

 // Copyright 2013 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.
 
 'use strict';
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
@@ skipping 193 matching lines @@
   }
   array.length = length;
   return array;
 }
 
 // -------------------------------------------------------------------
 
 function HarmonyArrayExtendSymbolPrototype() {
   %CheckIsBootstrapping();
 
-  InstallConstants($Symbol, $Array(
+  InstallConstants(global.Symbol, $Array(
     // TODO(dslomov, caitp): Move to symbol.js when shipping
    "isConcatSpreadable", symbolIsConcatSpreadable
   ));
 }
 
 HarmonyArrayExtendSymbolPrototype();
 
 function HarmonyArrayExtendArrayPrototype() {
   %CheckIsBootstrapping();
 
   %FunctionSetLength(ArrayFrom, 1);
 
   // Set up non-enumerable functions on the Array object.
   InstallFunctions($Array, DONT_ENUM, $Array(
     "from", ArrayFrom,
     "of", ArrayOf
   ));
 
   // Set up the non-enumerable functions on the Array prototype object.
   InstallFunctions($Array.prototype, DONT_ENUM, $Array(
     "find", ArrayFind,
     "findIndex", ArrayFindIndex,
     "fill", ArrayFill
   ));
 }
 
 HarmonyArrayExtendArrayPrototype();