Add three UseCounters for LABEL element.

third_party/WebKit/Source/core/html/HTMLLabelElement.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, 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 25 matching lines @@
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLLabelElement);
 public:
     static PassRefPtrWillBeRawPtr<HTMLLabelElement> create(Document&, HTMLFormElement*);
     LabelableElement* control() const;
 
     bool willRespondToMouseClickEvents() override;
 
     DECLARE_VIRTUAL_TRACE();
 
     HTMLFormElement* formOwner() const override;
+    HTMLFormElement* formForBinding() const;
 
 
 #if !ENABLE(OILPAN)
     using Node::ref;
     using Node::deref;
 #endif
 
 private:
     explicit HTMLLabelElement(Document&, HTMLFormElement*);
     bool isInInteractiveContent(Node*) const;
@@ skipping 45 matching lines @@
 {
     const HTMLLabelElement& labelElement = static_cast<const HTMLLabelElement&>(element);
     // FormAssociatedElement doesn't have hasTagName, hence check for assert.
     ASSERT_WITH_SECURITY_IMPLICATION(labelElement.hasTagName(HTMLNames::labelTag));
     return labelElement;
 }
 
 } // namespace blink
 
 #endif // HTMLLabelElement_h