Only 'form associated' elements have a potential form owner.

Source/core/html/HTMLObjectElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 19 matching lines @@
 
 class HTMLFormElement;
 
 class HTMLObjectElement FINAL : public HTMLPlugInElement, public FormAssociatedElement {
 public:
     static PassRefPtr<HTMLObjectElement> create(Document&, HTMLFormElement*, bool createdByParser);
     virtual ~HTMLObjectElement();
 
     const String& classId() const { return m_classId; }
 
+    virtual HTMLFormElement* formOwner() const OVERRIDE;
+
     bool containsJavaApplet() const;
 
     virtual bool useFallbackContent() const OVERRIDE;
     virtual void renderFallbackContent() OVERRIDE;
 
     virtual bool isFormControlElement() const { return false; }
 
     virtual bool isEnumeratable() const { return true; }
     virtual bool isInteractiveContent() const OVERRIDE;
     virtual bool appendFormData(FormDataList&, bool);
@@ skipping 44 matching lines @@
 
     // FIXME: This function should not deal with url or serviceType
     // so that we can better share code between <object> and <embed>.
     void parametersForPlugin(Vector<String>& paramNames, Vector<String>& paramValues, String& url, String& serviceType);
 
     bool shouldAllowQuickTimeClassIdQuirk();
     bool hasValidClassId();
 
     virtual void refFormAssociatedElement() { ref(); }
     virtual void derefFormAssociatedElement() { deref(); }
-    virtual HTMLFormElement* virtualForm() const;
 
     virtual bool shouldRegisterAsNamedItem() const OVERRIDE { return true; }
     virtual bool shouldRegisterAsExtraNamedItem() const OVERRIDE { return true; }
 
     String m_classId;
     bool m_useFallbackContent : 1;
 };
 
 DEFINE_NODE_TYPE_CASTS(HTMLObjectElement, hasTagName(HTMLNames::objectTag));
 
@@ skipping 13 matching lines @@
     const HTMLObjectElement& objectElement = static_cast<const HTMLObjectElement&>(element);
     // We need to assert after the cast because FormAssociatedElement doesn't
     // have hasTagName.
     ASSERT_WITH_SECURITY_IMPLICATION(objectElement.hasTagName(HTMLNames::objectTag));
     return objectElement;
 }
 
 }
 
 #endif