[ast cleanup] Remove unnecessary frozen_ bit from ModuleDescriptor

src/ast/modules.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_MODULES_H_
 #define V8_AST_MODULES_H_
 
 #include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 
 class AstRawString;
 
 
 class ModuleDescriptor : public ZoneObject {
  public:
   // ---------------------------------------------------------------------------
   // Factory methods.
 
   static ModuleDescriptor* New(Zone* zone) {
     return new (zone) ModuleDescriptor(zone);
   }
 
   // ---------------------------------------------------------------------------
   // Mutators.
 
-  // Add a name to the list of exports. If it already exists, or this descriptor
-  // is frozen, that's an error.
+  // Add a name to the list of exports. If it already exists, that's an error.
   void AddLocalExport(const AstRawString* export_name,
                       const AstRawString* local_name, Zone* zone, bool* ok);
 
   // Add module_specifier to the list of requested modules,
   // if not already present.
   void AddModuleRequest(const AstRawString* module_specifier, Zone* zone);
 
-  // Do not allow any further refinements, directly or through unification.
-  void Freeze() { frozen_ = true; }
-
   // Assign an index.
   void Allocate(int index) {
-    DCHECK(IsFrozen() && index_ == -1);
+    DCHECK_EQ(-1, index_);
     index_ = index;
   }
 
   // ---------------------------------------------------------------------------
   // Accessors.
 
-  // Check whether this is closed (i.e. fully determined).
-  bool IsFrozen() { return frozen_; }
-
   int Length() {
-    DCHECK(IsFrozen());
     ZoneHashMap* exports = exports_;
     return exports ? exports->occupancy() : 0;
   }
 
   // The context slot in the hosting script context pointing to this module.
   int Index() {
-    DCHECK(IsFrozen());
     return index_;
   }
 
   const AstRawString* LookupLocalExport(const AstRawString* export_name,
                                         Zone* zone);
 
   const ZoneList<const AstRawString*>& requested_modules() const {
     return requested_modules_;
   }
 
@@ skipping 25 matching lines @@
     const ZoneHashMap* exports_;
     ZoneHashMap::Entry* entry_;
   };
 
   Iterator iterator() const { return Iterator(this->exports_); }
 
   // ---------------------------------------------------------------------------
   // Implementation.
  private:
   explicit ModuleDescriptor(Zone* zone)
-      : frozen_(false),
-        exports_(NULL),
-        requested_modules_(1, zone),
-        index_(-1) {}
+      : exports_(NULL), requested_modules_(1, zone), index_(-1) {}
 
-  bool frozen_;
   ZoneHashMap* exports_;   // Module exports and their types (allocated lazily)
   ZoneList<const AstRawString*> requested_modules_;
   int index_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_MODULES_H_