Remove unused Zone argument from InitializeAstVisitor

src/compiler/ast-loop-assignment-analyzer.h

 // 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.
 
 #ifndef V8_COMPILER_AST_LOOP_ASSIGNMENT_ANALYZER_H_
 #define V8_COMPILER_AST_LOOP_ASSIGNMENT_ANALYZER_H_
 
 #include "src/ast.h"
 #include "src/bit-vector.h"
 #include "src/zone-containers.h"
@@ skipping 35 matching lines @@
   LoopAssignmentAnalysis* Analyze();
 
 #define DECLARE_VISIT(type) void Visit##type(type* node) override;
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
   static int GetVariableIndex(Scope* scope, Variable* var);
 
  private:
   CompilationInfo* info_;
+  Zone* zone_;
   ZoneDeque<BitVector*> loop_stack_;
   LoopAssignmentAnalysis* result_;
 
   CompilationInfo* info() { return info_; }
 
   void Enter(IterationStatement* loop);
   void Exit(IterationStatement* loop);
 
   void VisitIfNotNull(AstNode* node) {
     if (node != NULL) Visit(node);
   }
 
   void AnalyzeAssignment(Variable* var);
 
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
   DISALLOW_COPY_AND_ASSIGN(AstLoopAssignmentAnalyzer);
 };
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_AST_LOOP_ASSIGNMENT_ANALYZER_H_