Enable ES6 iteration by default

src/preparser.cc

 // Copyright 2011 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.
 
 #include <cmath>
 
 #include "include/v8stdint.h"
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
@@ skipping 635 matching lines @@
   Expect(Token::LPAREN, CHECK_OK);
   ParseExpression(true, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
   ParseStatement(ok);
   return Statement::Default();
 }
 
 
 bool PreParser::CheckInOrOf(bool accept_OF) {
   if (Check(Token::IN) ||
-      (allow_for_of() && accept_OF &&
-       CheckContextualKeyword(CStrVector("of")))) {
+      (accept_OF && CheckContextualKeyword(CStrVector("of")))) {
     return true;
   }
   return false;
 }
 
 
 PreParser::Statement PreParser::ParseForStatement(bool* ok) {
   // ForStatement ::
   //   'for' '(' Expression? ';' Expression? ';' Expression? ')' Statement
 
@@ skipping 260 matching lines @@
   ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
   ParseArguments(ok);
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal