Use C++11 features in core/html

Source/core/html/RadioNodeList.cpp

 /*
  * Copyright (c) 2012 Motorola Mobility, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 37 matching lines @@
 RadioNodeList::~RadioNodeList()
 {
 #if !ENABLE(OILPAN)
     ownerNode().nodeLists()->removeCache(this, type(), m_name);
 #endif
 }
 
 static inline HTMLInputElement* toRadioButtonInputElement(Element& element)
 {
     if (!isHTMLInputElement(element))
-        return 0;
+        return nullptr;
     HTMLInputElement& inputElement = toHTMLInputElement(element);
     if (inputElement.type() != InputTypeNames::radio || inputElement.value().isEmpty())
-        return 0;
+        return nullptr;
     return &inputElement;
 }
 
 String RadioNodeList::value() const
 {
     if (shouldOnlyMatchImgElements())
         return String();
     unsigned length = this->length();
     for (unsigned i = 0; i < length; ++i) {
         const HTMLInputElement* inputElement = toRadioButtonInputElement(*item(i));
@@ skipping 51 matching lines @@
     if (!isHTMLObjectElement(element) && !element.isFormControlElement())
         return false;
 
     if (isHTMLInputElement(element) && toHTMLInputElement(element).type() == InputTypeNames::image)
         return false;
 
     return checkElementMatchesRadioNodeListFilter(element);
 }
 
 } // namespace