Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/html/track/vtt/VTTCue.cpp

 /*
  * Copyright (c) 2013, Opera Software ASA. 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 192 matching lines @@
 
 VTTCue::VTTCue(Document& document, double startTime, double endTime, const String& text)
     : TextTrackCue(startTime, endTime)
     , m_text(text)
     , m_linePosition(undefinedPosition)
     , m_computedLinePosition(undefinedPosition)
     , m_textPosition(50)
     , m_cueSize(100)
     , m_writingDirection(Horizontal)
     , m_cueAlignment(Middle)
-    , m_vttNodeTree(0)
+    , m_vttNodeTree(nullptr)
     , m_cueBackgroundBox(HTMLDivElement::create(document))
     , m_displayDirection(CSSValueLtr)
     , m_displaySize(undefinedSize)
     , m_snapToLines(true)
     , m_displayTreeShouldChange(true)
     , m_notifyRegion(true)
 {
     ScriptWrappable::init(this);
 }
 
@@ skipping 177 matching lines @@
 }
 
 void VTTCue::setText(const String& text)
 {
     if (m_text == text)
         return;
 
     cueWillChange();
     // Clear the document fragment but don't bother to create it again just yet as we can do that
     // when it is requested.
-    m_vttNodeTree = 0;
+    m_vttNodeTree = nullptr;
     m_text = text;
     cueDidChange();
 }
 
 void VTTCue::createVTTNodeTree()
 {
     if (!m_vttNodeTree)
         m_vttNodeTree = VTTParser::createDocumentFragmentFromCueText(document(), m_text);
 }
 
@@ skipping 643 matching lines @@
     return m_cueBackgroundBox->executionContext();
 }
 
 Document& VTTCue::document() const
 {
     ASSERT(m_cueBackgroundBox);
     return m_cueBackgroundBox->document();
 }
 
 } // namespace WebCore