Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/clipboard/DataObject.cpp

 /*
  * Copyright (c) 2008, 2009, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 57 matching lines @@
 }
 
 size_t DataObject::length() const
 {
     return m_itemList.size();
 }
 
 PassRefPtr<DataObjectItem> DataObject::item(unsigned long index)
 {
     if (index >= length())
-        return 0;
+        return nullptr;
     return m_itemList[index];
 }
 
 void DataObject::deleteItem(unsigned long index)
 {
     if (index >= length())
         return;
     m_itemList.remove(index);
 }
 
 void DataObject::clearAll()
 {
     m_itemList.clear();
 }
 
 PassRefPtr<DataObjectItem> DataObject::add(const String& data, const String& type)
 {
     RefPtr<DataObjectItem> item = DataObjectItem::createFromString(type, data);
     if (!internalAddStringItem(item))
-        return 0;
+        return nullptr;
     return item;
 }
 
 PassRefPtr<DataObjectItem> DataObject::add(PassRefPtr<File> file)
 {
     if (!file)
-        return 0;
+        return nullptr;
 
     RefPtr<DataObjectItem> item = DataObjectItem::createFromFile(file);
     m_itemList.append(item);
     return item;
 }
 
 void DataObject::clearData(const String& type)
 {
     for (size_t i = 0; i < m_itemList.size(); ++i) {
         if (m_itemList[i]->kind() == DataObjectItem::StringKind && m_itemList[i]->type() == type) {
@@ skipping 122 matching lines @@
     , m_modifierKeyState(0)
 {
 }
 
 PassRefPtr<DataObjectItem> DataObject::findStringItem(const String& type) const
 {
     for (size_t i = 0; i < m_itemList.size(); ++i) {
         if (m_itemList[i]->kind() == DataObjectItem::StringKind && m_itemList[i]->type() == type)
             return m_itemList[i];
     }
-    return 0;
+    return nullptr;
 }
 
 bool DataObject::internalAddStringItem(PassRefPtr<DataObjectItem> item)
 {
     ASSERT(item->kind() == DataObjectItem::StringKind);
     for (size_t i = 0; i < m_itemList.size(); ++i) {
         if (m_itemList[i]->kind() == DataObjectItem::StringKind && m_itemList[i]->type() == item->type())
             return false;
     }
 
     m_itemList.append(item);
     return true;
 }
 
 void DataObject::internalAddFileItem(PassRefPtr<DataObjectItem> item)
 {
     ASSERT(item->kind() == DataObjectItem::FileKind);
     m_itemList.append(item);
 }
 
 } // namespace WebCore