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

Source/bindings/v8/custom/V8HTMLAllCollectionCustom.cpp

 /*
  * Copyright (C) 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 53 matching lines @@
     if (index.IsEmpty()) {
         V8TRYCATCH_FOR_V8STRINGRESOURCE_RETURN(V8StringResource<>, name, argument, v8::Undefined(info.GetIsolate()));
         v8::Handle<v8::Value> result = getNamedItems(collection, name, info);
 
         if (result.IsEmpty())
             return v8::Undefined(info.GetIsolate());
 
         return result;
     }
 
-    RefPtr<Node> result = collection->item(index->Uint32Value());
+    RefPtr<Element> result = collection->item(index->Uint32Value());
     return toV8(result.release(), info.Holder(), info.GetIsolate());
 }
 
 void V8HTMLAllCollection::itemMethodCustom(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
     HTMLAllCollection* imp = V8HTMLAllCollection::toNative(info.Holder());
     v8SetReturnValue(info, getItem(imp, info[0], info));
 }
 
 void V8HTMLAllCollection::namedItemMethodCustom(const v8::FunctionCallbackInfo<v8::Value>& info)
@@ skipping 33 matching lines @@
     if (index.IsEmpty())
         return;
 
     if (Node* node = imp->namedItemWithIndex(name, index->Uint32Value())) {
         v8SetReturnValueFast(info, node, imp);
         return;
     }
 }
 
 } // namespace WebCore