Fix garbage collection of unused maps. Null descriptors, created...

src/property.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 338 matching lines @@
   bool IsTransition() {
     PropertyType t = type();
     ASSERT(t != INTERCEPTOR);
     return t == MAP_TRANSITION || t == CONSTANT_TRANSITION;
   }
 
   bool IsNullDescriptor() {
     return type() == NULL_DESCRIPTOR;
   }
 
+  bool IsProperty() {
+    return type() < FIRST_PHANTOM_PROPERTY_TYPE;
+  }
+
   JSFunction* GetConstantFunction() { return JSFunction::cast(GetValue()); }
 
   AccessorDescriptor* GetCallbacks() {
     ASSERT(type() == CALLBACKS);
     Proxy* p = Proxy::cast(GetCallbacksObject());
     return reinterpret_cast<AccessorDescriptor*>(p->proxy());
   }
 
   Object* GetCallbacksObject() {
     ASSERT(type() == CALLBACKS);
@@ skipping 14 matching lines @@
 
   // Append a descriptor to this stream.
   void Write(Descriptor* desc);
   // Read a descriptor from the reader and append it to this stream.
   void WriteFrom(DescriptorReader* reader);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROPERTY_H_