Have HTMLCollection::item() return an Element as per specification

Source/web/WebHelperPluginImpl.cpp

 /*
  * Copyright (C) 2012 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 166 matching lines @@
 
 // Returns a pointer to the WebPlugin by finding the single <object> tag in the page.
 WebPlugin* WebHelperPluginImpl::getPlugin()
 {
     ASSERT(m_page);
 
     RefPtr<HTMLCollection> objectElements = m_page->mainFrame()->document()->getElementsByTagName(WebCore::HTMLNames::objectTag.localName());
     ASSERT(objectElements && objectElements->length() == 1);
     if (!objectElements || objectElements->length() < 1)
         return 0;
-    Node* node = objectElements->item(0);
-    ASSERT(node->hasTagName(WebCore::HTMLNames::objectTag));
-    WebCore::Widget* widget = toHTMLPlugInElement(node)->pluginWidget();
+    Element* element = objectElements->item(0);
+    ASSERT(element->hasTagName(WebCore::HTMLNames::objectTag));
+    WebCore::Widget* widget = toHTMLPlugInElement(element)->pluginWidget();
     if (!widget)
         return 0;
     WebPlugin* plugin = toWebPluginContainerImpl(widget)->plugin();
     ASSERT(plugin);
     // If the plugin is a placeholder, it is not useful to the caller, and it
     // could be replaced at any time. Therefore, do not return it.
     if (plugin->isPlaceholder())
         return 0;
 
     // The plugin was instantiated and will outlive this object.
@@ skipping 60 matching lines @@
 {
     RELEASE_ASSERT(client);
 
     // The returned object is owned by the caller, which must destroy it by
     // calling closeAndDelete(). The WebWidgetClient must not call close()
     // other than as a result of closeAndDelete().
     return new WebHelperPluginImpl(client);
 }
 
 } // namespace blink