Implement HTMLOptionElement.form as required by spec.

Source/core/html/HTMLOptionElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2004, 2005, 2006, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2011 Motorola Mobility, Inc.  All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 348 matching lines @@
             text.append(node->nodeValue());
         // Text nodes inside script elements are not part of the option text.
         if (node->isElementNode() && toScriptLoaderIfPossible(toElement(node)))
             node = NodeTraversal::nextSkippingChildren(*node, this);
         else
             node = NodeTraversal::next(*node, this);
     }
     return text.toString();
 }
 
+HTMLFormElement* HTMLOptionElement::form() const
+{
+    HTMLSelectElement* selectElement = ownerSelectElement();

[tkent, 2013/12/10 23:09:08]

nit:

if (HTMLSelectElement* selectElement = ownerSelectElement())
    return selectElement->formOwner();
return 0;

is simpler.

+    if (!selectElement)
+        return 0;
+
+    return selectElement->formOwner();
+}
+
 } // namespace WebCore