Convert DOMWrapperMap to use PersistentValueMap

Source/bindings/v8/V8NPObject.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Google Inc. 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
@@ skipping 44 matching lines @@
 // If the object is already wrapped, the pre-existing wrapper will be returned. If the object is not wrapped, wrap it, and
 // give V8 a weak reference to the wrapper which will cleanup when there are no more JS references to the object.
 v8::Local<v8::Object> createV8ObjectForNPObject(NPObject*, NPObject* root, v8::Isolate*);
 
 // Tell V8 to forcibly remove an object.
 // This is used at plugin teardown so that the caller can aggressively unload the plugin library. After calling this
 // function, the persistent handle to the wrapper will be gone, and the wrapped NPObject will be removed so that it
 // cannot be referred to.
 void forgetV8ObjectForNPObject(NPObject*);
 
+// Helper function for DOMWrapperMap<NPObject>.
+// Dispose of the fiven NPObject*.
+void DOMWrapperMapDisposeHelper(NPObject*);
+
 } // namespace WebCore
 
 #endif // V8NPObject_h