Limit the usage of SharedPersistent to ScriptValue only

Source/bindings/v8/V8NPObject.cpp

 /*
 * 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 63 matching lines @@
     if (V8HTMLAppletElement::hasInstance(info.Holder(), info.GetIsolate()) || V8HTMLEmbedElement::hasInstance(info.Holder(), info.GetIsolate())
         || V8HTMLObjectElement::hasInstance(info.Holder(), info.GetIsolate())) {
         // The holder object is a subtype of HTMLPlugInElement.
         HTMLPlugInElement* element;
         if (V8HTMLAppletElement::hasInstance(info.Holder(), info.GetIsolate()))
             element = V8HTMLAppletElement::toNative(info.Holder());
         else if (V8HTMLEmbedElement::hasInstance(info.Holder(), info.GetIsolate()))
             element = V8HTMLEmbedElement::toNative(info.Holder());
         else
             element = V8HTMLObjectElement::toNative(info.Holder());
-        if (RefPtr<SharedPersistent<v8::Object> > wrapper = element->pluginWrapper()) {
+        ScriptValue wrapper = element->pluginWrapper();
+        if (!wrapper.hasNoValue()) {
             v8::Isolate* isolate = v8::Isolate::GetCurrent();
             v8::HandleScope handleScope(isolate);
-            npObject = v8ObjectToNPObject(wrapper->newLocal(isolate));
+            npObject = v8ObjectToNPObject(v8::Handle<v8::Object>::Cast(wrapper.v8Value()));
         } else
             npObject = 0;
     } else {
         // The holder object is not a subtype of HTMLPlugInElement, it must be an NPObject which has three
         // internal fields.
         if (info.Holder()->InternalFieldCount() != npObjectInternalFieldCount) {
             throwError(v8ReferenceError, "NPMethod called on non-NPObject", info.GetIsolate());
             return;
         }
 
@@ skipping 379 matching lines @@
     v8::HandleScope scope(isolate);
     v8::Handle<v8::Object> wrapper = staticNPObjectMap().newLocal(object, isolate);
     if (!wrapper.IsEmpty()) {
         V8DOMWrapper::clearNativeInfo(wrapper, npObjectTypeInfo());
         staticNPObjectMap().removeAndDispose(object);
         _NPN_ReleaseObject(object);
     }
 }
 
 } // namespace WebCore