diff -r 000000000000 -r 4f2f89ce4247 WebCore/dom/CheckedRadioButtons.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/dom/CheckedRadioButtons.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 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.
+ *
+ * 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 "config.h"
+#include "CheckedRadioButtons.h"
+
+#include "HTMLInputElement.h"
+
+namespace WebCore {
+
+void CheckedRadioButtons::addButton(HTMLFormControlElement* element)
+{
+    // We only want to add radio buttons.
+    if (!element->isRadioButton())
+        return;
+
+    // Without a name, there is no group.
+    if (element->name().isEmpty())
+        return;
+
+    HTMLInputElement* inputElement = static_cast<HTMLInputElement*>(element);
+
+    // We only track checked buttons.
+    if (!inputElement->checked())
+        return;
+
+    if (!m_nameToCheckedRadioButtonMap)
+        m_nameToCheckedRadioButtonMap.set(new NameToInputMap);
+
+    pair<NameToInputMap::iterator, bool> result = m_nameToCheckedRadioButtonMap->add(element->name().impl(), inputElement);
+    if (result.second)
+        return;
+    
+    HTMLInputElement* oldCheckedButton = result.first->second;
+    if (oldCheckedButton == inputElement)
+        return;
+
+    result.first->second = inputElement;
+    oldCheckedButton->setChecked(false);
+}
+
+HTMLInputElement* CheckedRadioButtons::checkedButtonForGroup(const AtomicString& name) const
+{
+    if (!m_nameToCheckedRadioButtonMap)
+        return 0;
+
+    m_nameToCheckedRadioButtonMap->checkConsistency();
+    
+    return m_nameToCheckedRadioButtonMap->get(name.impl());
+}
+
+void CheckedRadioButtons::removeButton(HTMLFormControlElement* element)
+{
+    if (element->name().isEmpty() || !m_nameToCheckedRadioButtonMap)
+        return;
+    
+    m_nameToCheckedRadioButtonMap->checkConsistency();
+
+    NameToInputMap::iterator it = m_nameToCheckedRadioButtonMap->find(element->name().impl());
+    if (it == m_nameToCheckedRadioButtonMap->end() || it->second != element)
+        return;
+    
+    InputElement* inputElement = toInputElement(element);
+    ASSERT_UNUSED(inputElement, inputElement);
+    ASSERT(inputElement->isChecked());
+    ASSERT(element->isRadioButton());
+
+    m_nameToCheckedRadioButtonMap->remove(it);
+    if (m_nameToCheckedRadioButtonMap->isEmpty())
+        m_nameToCheckedRadioButtonMap.clear();
+}
+
+} // namespace