Fix invalid use of int in Zone.

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/v8.h"
 
 #include "src/assembler.h"
@@ skipping 182 matching lines @@
 
 class AstNode: public ZoneObject {
  public:
 #define DECLARE_TYPE_ENUM(type) k##type,
   enum NodeType {
     AST_NODE_LIST(DECLARE_TYPE_ENUM)
     kInvalid = -1
   };
 #undef DECLARE_TYPE_ENUM
 
-  void* operator new(size_t size, Zone* zone) {
-    return zone->New(static_cast<int>(size));
-  }
+  void* operator new(size_t size, Zone* zone) { return zone->New(size); }
 
   explicit AstNode(int position): position_(position) {}
   virtual ~AstNode() {}
 
   virtual void Accept(AstVisitor* v) = 0;
   virtual NodeType node_type() const = 0;
   int position() const { return position_; }
 
   // Type testing & conversion functions overridden by concrete subclasses.
 #define DECLARE_NODE_FUNCTIONS(type) \
@@ skipping 3324 matching lines @@
 
  private:
   Zone* zone_;
   AstValueFactory* ast_value_factory_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_