Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/clipboard/DataObjectItem.cpp

 /*
  * Copyright (C) 2011 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 85 matching lines @@
     : m_source(PasteboardSource)
     , m_kind(kind)
     , m_type(type)
     , m_sequenceNumber(sequenceNumber)
 {
 }
 
 PassRefPtr<Blob> DataObjectItem::getAsFile() const
 {
     if (kind() != FileKind)
-        return 0;
+        return nullptr;
 
     if (m_source == InternalSource) {
         if (m_file)
             return m_file;
         ASSERT(m_sharedBuffer);
         // FIXME: This code is currently impossible--we never populate m_sharedBuffer when dragging
         // in. At some point though, we may need to support correctly converting a shared buffer
         // into a file.
-        return 0;
+        return nullptr;
     }
 
     ASSERT(m_source == PasteboardSource);
     if (type() == mimeTypeImagePng) {
         // FIXME: This is pretty inefficient. We copy the data from the browser
         // to the renderer. We then place it in a blob in WebKit, which
         // registers it and copies it *back* to the browser. When a consumer
         // wants to read the data, we then copy the data back into the renderer.
         // https://bugs.webkit.org/show_bug.cgi?id=58107 has been filed to track
         // improvements to this code (in particular, add a registerClipboardBlob
         // method to the blob registry; that way the data is only copied over
         // into the renderer when it's actually read, not when the blob is
         // initially constructed).
         RefPtr<SharedBuffer> data = static_cast<PassRefPtr<SharedBuffer> >(blink::Platform::current()->clipboard()->readImage(blink::WebClipboard::BufferStandard));
         RefPtr<RawData> rawData = RawData::create();
         rawData->mutableData()->append(data->data(), data->size());
         OwnPtr<BlobData> blobData = BlobData::create();
         blobData->appendData(rawData, 0, -1);
         blobData->setContentType(mimeTypeImagePng);
         return Blob::create(BlobDataHandle::create(blobData.release(), data->size()));
     }
 
-    return 0;
+    return nullptr;
 }
 
 String DataObjectItem::getAsString() const
 {
     ASSERT(m_kind == StringKind);
 
     if (m_source == InternalSource)
         return m_data;
 
     ASSERT(m_source == PasteboardSource);
@@ skipping 16 matching lines @@
 
 bool DataObjectItem::isFilename() const
 {
     // FIXME: https://bugs.webkit.org/show_bug.cgi?id=81261: When we properly support File dragout,
     // we'll need to make sure this works as expected for DragDataChromium.
     return m_kind == FileKind && m_file;
 }
 
 } // namespace WebCore