Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/animation/Animation.cpp

 /*
  * Copyright (C) 2013 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 50 matching lines @@
     return true;
 }
 
 PassRefPtr<Animation> Animation::create(Element* element, Vector<Dictionary> keyframeDictionaryVector, Dictionary timingInput)
 {
     ASSERT(RuntimeEnabledFeatures::webAnimationsAPIEnabled());
 
     // FIXME: This test will not be neccessary once resolution of keyframe values occurs at
     // animation application time.
     if (!checkDocumentAndRenderer(element))
-        return 0;
+        return nullptr;
 
     return createUnsafe(element, keyframeDictionaryVector, timingInput);
 }
 
 PassRefPtr<Animation> Animation::create(Element* element, Vector<Dictionary> keyframeDictionaryVector, double timingInput)
 {
     ASSERT(RuntimeEnabledFeatures::webAnimationsAPIEnabled());
 
     // FIXME: This test will not be neccessary once resolution of keyframe values occurs at
     // animation application time.
     if (!checkDocumentAndRenderer(element))
-        return 0;
+        return nullptr;
 
     return createUnsafe(element, keyframeDictionaryVector, timingInput);
 }
 
 PassRefPtr<Animation> Animation::create(Element* element, Vector<Dictionary> keyframeDictionaryVector)
 {
     ASSERT(RuntimeEnabledFeatures::webAnimationsAPIEnabled());
 
     // FIXME: This test will not be neccessary once resolution of keyframe values occurs at
     // animation application time.
     if (!checkDocumentAndRenderer(element))
-        return 0;
+        return nullptr;
 
     return createUnsafe(element, keyframeDictionaryVector);
 }
 
 void Animation::setStartDelay(Timing& timing, double startDelay)
 {
     if (std::isfinite(startDelay))
         timing.startDelay = startDelay;
     else
         timing.startDelay = 0;
@@ skipping 372 matching lines @@
 void Animation::pauseAnimationForTestingOnCompositor(double pauseTime)
 {
     ASSERT(hasActiveAnimationsOnCompositor());
     if (!m_target || !m_target->renderer())
         return;
     for (size_t i = 0; i < m_compositorAnimationIds.size(); ++i)
         CompositorAnimations::instance()->pauseAnimationForTestingOnCompositor(*m_target.get(), m_compositorAnimationIds[i], pauseTime);
 }
 
 } // namespace WebCore