Remove the SetExternalStringDiposeCallback API...

src/heap-inl.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 100 matching lines @@
 
 
 void Heap::FinalizeExternalString(String* string) {
   ASSERT(string->IsExternalString());
   v8::String::ExternalStringResourceBase** resource_addr =
       reinterpret_cast<v8::String::ExternalStringResourceBase**>(
           reinterpret_cast<byte*>(string) +
           ExternalString::kResourceOffset -
           kHeapObjectTag);
 
-  // Dispose of the C++ object.
-  if (external_string_dispose_callback_ != NULL) {
-    external_string_dispose_callback_(*resource_addr);
-  } else {
-    delete *resource_addr;
+  // Dispose of the C++ object if it has not already been disposed.
+  if (*resource_addr != NULL) {
+    (*resource_addr)->Dispose();
   }
 
   // Clear the resource pointer in the string.
   *resource_addr = NULL;
 }
 
 
 Object* Heap::AllocateRawMap() {
 #ifdef DEBUG
   Counters::objs_since_last_full.Increment();
@@ skipping 353 matching lines @@
 
 
 void ExternalStringTable::ShrinkNewStrings(int position) {
   new_space_strings_.Rewind(position);
   Verify();
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_