Wrap harmony implementations in functions.

src/harmony-regexp.js

 // Copyright 2014 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() {
+
 'use strict';
 
-var $RegExp = global.RegExp;
+%CheckIsBootstrapping();
+
+var GlobalRegExp = global.RegExp;
 
 // -------------------------------------------------------------------
 
 // ES6 draft 12-06-13, section 21.2.5.3
 // + https://bugs.ecmascript.org/show_bug.cgi?id=3423
 function RegExpGetFlags() {
   if (!IS_SPEC_OBJECT(this)) {
     throw MakeTypeError('flags_getter_non_object',
                         [%ToString(this)]);
   }
   var result = '';
   if (this.global) result += 'g';
   if (this.ignoreCase) result += 'i';
   if (this.multiline) result += 'm';
   if (this.unicode) result += 'u';
   if (this.sticky) result += 'y';
   return result;
 }
 
-function ExtendRegExpPrototype() {
-  %CheckIsBootstrapping();
+%DefineAccessorPropertyUnchecked(GlobalRegExp.prototype, 'flags',
+                                 RegExpGetFlags, null, DONT_ENUM);
+%SetNativeFlag(RegExpGetFlags);
 
-  %DefineAccessorPropertyUnchecked($RegExp.prototype, 'flags', RegExpGetFlags,
-                                   null, DONT_ENUM);
-  %SetNativeFlag(RegExpGetFlags);
-}
-
-ExtendRegExpPrototype();
+})();