Experiment with restricting form submission with open elements.

third_party/WebKit/Source/core/html/HTMLFormControlElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 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
@@ skipping 114 matching lines @@
 
   static HTMLFormControlElement* enclosingFormControlElement(Node*);
 
   String nameForAutofill() const;
 
   void copyNonAttributePropertiesFromElement(const Element&) override;
 
   FormAssociated* toFormAssociatedOrNull() override { return this; };
   void associateWith(HTMLFormElement*) override;
 
+  bool blocksFormSubmission() const { return m_blocksFormSubmission; }
+  void setBlocksFormSubmission(bool value) { m_blocksFormSubmission = value; }
+
  protected:
   HTMLFormControlElement(const QualifiedName& tagName, Document&);
 
   void attributeChanged(const AttributeModificationParams&) override;
   void parseAttribute(const AttributeModificationParams&) override;
   virtual void requiredAttributeChanged();
   virtual void disabledAttributeChanged();
   void attachLayoutTree(const AttachContext& = AttachContext()) override;
   InsertionNotificationRequest insertedInto(ContainerNode*) override;
   void removedFrom(ContainerNode*) override;
@@ skipping 55 matching lines @@
   // initialize it with a virtual function in the constructor. m_willValidate
   // is not deterministic as long as m_willValidateInitialized is false.
   mutable bool m_willValidateInitialized : 1;
   mutable bool m_willValidate : 1;
 
   // Cache of valid().
   bool m_isValid : 1;
   bool m_validityIsDirty : 1;
 
   bool m_wasFocusedByMouse : 1;
+  bool m_blocksFormSubmission : 1;
 };
 
 inline bool isHTMLFormControlElement(const Element& element) {
   return element.isFormControlElement();
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLFormControlElement);
 DEFINE_TYPE_CASTS(HTMLFormControlElement,
                   ListedElement,
                   control,
                   control->isFormControlElement(),
                   control.isFormControlElement());
 
 }  // namespace blink
 
 #endif