Allocate script scopes using a separate constructor

src/ast/scopes.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_SCOPES_H_
 #define V8_AST_SCOPES_H_
 
 #include "src/ast/ast.h"
 #include "src/base/hashmap.h"
 #include "src/globals.h"
@@ skipping 428 matching lines @@
 
   // Check that all Scopes in the scope tree use the same Zone.
   void CheckZones();
 #endif
 
   // Retrieve `IsSimpleParameterList` of current or outer function.
   bool HasSimpleParameters();
   void set_is_debug_evaluate_scope() { is_debug_evaluate_scope_ = true; }
 
  protected:
+  // Creates a script scope.
+  explicit Scope(Zone* zone);
+
   void set_language_mode(LanguageMode language_mode) {
     is_strict_ = is_strict(language_mode);
   }
 
  private:
   Variable* Declare(Zone* zone, Scope* scope, const AstRawString* name,
                     VariableMode mode, Variable::Kind kind,
                     InitializationFlag initialization_flag,
                     MaybeAssignedFlag maybe_assigned_flag = kNotAssigned) {
     bool added;
@@ skipping 196 matching lines @@
 
   friend class DeclarationScope;
 };
 
 class DeclarationScope : public Scope {
  public:
   DeclarationScope(Zone* zone, Scope* outer_scope, ScopeType scope_type,
                    FunctionKind function_kind = kNormalFunction);
   DeclarationScope(Zone* zone, Scope* inner_scope, ScopeType scope_type,
                    Handle<ScopeInfo> scope_info);
+  // Creates a script scope.
+  explicit DeclarationScope(Zone* zone);
 
   bool IsDeclaredParameter(const AstRawString* name) {
     // If IsSimpleParameterList is false, duplicate parameters are not allowed,
     // however `arguments` may be allowed if function is not strict code. Thus,
     // the assumptions explained above do not hold.
     return params_.Contains(variables_.Lookup(name));
   }
 
   FunctionKind function_kind() const { return function_kind_; }
 
@@ skipping 234 matching lines @@
   void AllocateModuleVariables();
 
  private:
   ModuleDescriptor* module_descriptor_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_SCOPES_H_