Drop LABEL element from form-associated elements.

third_party/WebKit/Source/core/html/LabelsNodeList.cpp

 /**
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/html/LabelsNodeList.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/Element.h"
 #include "core/dom/NodeRareData.h"
 #include "core/html/HTMLLabelElement.h"
+#include "core/html/LabelableElement.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 LabelsNodeList::LabelsNodeList(ContainerNode& ownerNode)
     : LiveNodeList(ownerNode, LabelsNodeListType, InvalidateOnForAttrChange, NodeListRootType::TreeScope)
 {
 }
 
 LabelsNodeList::~LabelsNodeList()
 {
 }
 
 bool LabelsNodeList::elementMatches(const Element& element) const
 {
     return isHTMLLabelElement(element) && toHTMLLabelElement(element).control() == ownerNode();
 }
 
 } // namespace blink