Remove unused Zone argument from InitializeAstVisitor

src/ast.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_AST_H_
 #define V8_AST_H_
 
 #include "src/assembler.h"
 #include "src/ast-value-factory.h"
 #include "src/bailout-reason.h"
@@ skipping 3172 matching lines @@
   bool CheckStackOverflow() {                               \
     if (stack_overflow_) return true;                       \
     if (GetCurrentStackPosition() < stack_limit_) {         \
       stack_overflow_ = true;                               \
       return true;                                          \
     }                                                       \
     return false;                                           \
   }                                                         \
                                                             \
  private:                                                   \
-  void InitializeAstVisitor(Isolate* isolate, Zone* zone) { \
-    zone_ = zone;                                           \
+  void InitializeAstVisitor(Isolate* isolate) {             \
     stack_limit_ = isolate->stack_guard()->real_climit();   \
     stack_overflow_ = false;                                \
   }                                                         \
-  Zone* zone() { return zone_; }                            \
                                                             \
-  Zone* zone_;                                              \
   uintptr_t stack_limit_;                                   \
   bool stack_overflow_
 
 
 // ----------------------------------------------------------------------------
 // AstNode factory
 
 class AstNodeFactory final BASE_EMBEDDED {
  public:
   explicit AstNodeFactory(AstValueFactory* ast_value_factory)
@@ skipping 425 matching lines @@
   // the parser-level zone.
   Zone* parser_zone_;
   AstValueFactory* ast_value_factory_;
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_H_