Do not save/restore AST id generator.

src/parser.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_PARSER_H_
 #define V8_PARSER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/compiler.h"  // For CachedDataMode
@@ skipping 356 matching lines @@
     typedef v8::internal::Literal* Literal;
     typedef ObjectLiteral::Property* ObjectLiteralProperty;
     typedef ZoneList<v8::internal::Expression*>* ExpressionList;
     typedef ZoneList<ObjectLiteral::Property*>* PropertyList;
     typedef ZoneList<v8::internal::Statement*>* StatementList;
 
     // For constructing objects returned by the traversing functions.
     typedef AstNodeFactory<AstConstructionVisitor> Factory;
   };
 
-  class Checkpoint;
-
   explicit ParserTraits(Parser* parser) : parser_(parser) {}
 
   // Custom operations executed when FunctionStates are created and destructed.
   template <typename FunctionState>
   static void SetUpFunctionState(FunctionState* function_state) {
     function_state->saved_id_gen_ = *function_state->ast_node_id_gen_;
     *function_state->ast_node_id_gen_ =
         AstNode::IdGen(BailoutId::FirstUsable().ToInt());
   }
 
@@ skipping 536 matching lines @@
  private:
   static const int kLiteralTypeSlot = 0;
   static const int kElementsSlot = 1;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(CompileTimeValue);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_