Parser: store parameters in a ThreadedList instead of ZoneList.

src/parsing/parser-base.h

 // Copyright 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.
 
 #ifndef V8_PARSING_PARSER_BASE_H
 #define V8_PARSING_PARSER_BASE_H
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/bailout-reason.h"
@@ skipping 3482 matching lines @@
         break;
       }
       if (!Check(Token::COMMA)) break;
       if (allow_harmony_trailing_commas() && peek() == Token::RPAREN) {
         // allow the trailing comma
         break;
       }
     }
   }
 
-  for (int i = 0; i < parameters->arity; ++i) {
-    auto parameter = parameters->at(i);
-    impl()->DeclareFormalParameter(parameters->scope, parameter);
-  }
+  impl()->DeclareFormalParameters(parameters->scope, parameters->params);
 }
 
 template <typename Impl>
 typename ParserBase<Impl>::BlockT ParserBase<Impl>::ParseVariableDeclarations(
     VariableDeclarationContext var_context,
     DeclarationParsingResult* parsing_result,
     ZoneList<const AstRawString*>* names, bool* ok) {
   // VariableDeclarations ::
   //   ('var' | 'const' | 'let') (Identifier ('=' AssignmentExpression)?)+[',']
   //
@@ skipping 1940 matching lines @@
     has_seen_constructor_ = true;
     return;
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_BASE_H