Use nullptr instead of 0 in xml and xmlhttprequest.

Source/core/xml/XPathResult.cpp

 /*
  * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006, 2009 Apple 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.
@@ skipping 137 matching lines @@
         exceptionState.throwTypeError("The result type is not a boolean.");
         return false;
     }
     return m_value.toBoolean();
 }
 
 Node* XPathResult::singleNodeValue(ExceptionState& exceptionState) const
 {
     if (resultType() != ANY_UNORDERED_NODE_TYPE && resultType() != FIRST_ORDERED_NODE_TYPE) {
         exceptionState.throwTypeError("The result type is not a single node.");
-        return 0;
+        return nullptr;
     }
 
     const NodeSet& nodes = m_value.toNodeSet(0);
     if (resultType() == FIRST_ORDERED_NODE_TYPE)
         return nodes.firstNode();
     return nodes.anyNode();
 }
 
 bool XPathResult::invalidIteratorState() const
 {
@@ skipping 11 matching lines @@
         return 0;
     }
 
     return m_value.toNodeSet(0).size();
 }
 
 Node* XPathResult::iterateNext(ExceptionState& exceptionState)
 {
     if (resultType() != UNORDERED_NODE_ITERATOR_TYPE && resultType() != ORDERED_NODE_ITERATOR_TYPE) {
         exceptionState.throwTypeError("The result type is not an iterator.");
-        return 0;
+        return nullptr;
     }
 
     if (invalidIteratorState()) {
         exceptionState.throwDOMException(InvalidStateError, "The document has mutated since the result was returned.");
-        return 0;
+        return nullptr;
     }
 
     if (m_nodeSetPosition + 1 > nodeSet().size())
-        return 0;
+        return nullptr;
 
     Node* node = nodeSet()[m_nodeSetPosition];
 
     m_nodeSetPosition++;
 
     return node;
 }
 
 Node* XPathResult::snapshotItem(unsigned index, ExceptionState& exceptionState)
 {
     if (resultType() != UNORDERED_NODE_SNAPSHOT_TYPE && resultType() != ORDERED_NODE_SNAPSHOT_TYPE) {
         exceptionState.throwTypeError("The result type is not a snapshot.");
-        return 0;
+        return nullptr;
     }
 
     const NodeSet& nodes = m_value.toNodeSet(0);
     if (index >= nodes.size())
-        return 0;
+        return nullptr;
 
     return nodes[index];
 }
 
 }