Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/modules/filesystem/DOMFileSystemSync.cpp

 /*
  * Copyright (C) 2010 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 152 matching lines @@
 
 } // namespace
 
 PassRefPtr<File> DOMFileSystemSync::createFile(const FileEntrySync* fileEntry, ExceptionState& exceptionState)
 {
     KURL fileSystemURL = createFileSystemURL(fileEntry);
     RefPtr<CreateFileHelper::CreateFileResult> result(CreateFileHelper::CreateFileResult::create());
     fileSystem()->createSnapshotFileAndReadMetadata(fileSystemURL, CreateFileHelper::create(result, fileEntry->name(), fileSystemURL, type()));
     if (result->m_failed) {
         exceptionState.throwDOMException(result->m_code, "Could not create '" + fileEntry->name() + "'.");
-        return 0;
+        return nullptr;
     }
     return result->m_file;
 }
 
 namespace {
 
 class ReceiveFileWriterCallback FINAL : public FileWriterBaseCallback {
 public:
     static PassOwnPtr<ReceiveFileWriterCallback> create()
     {
@@ skipping 42 matching lines @@
     OwnPtr<ReceiveFileWriterCallback> successCallback = ReceiveFileWriterCallback::create();
     FileError::ErrorCode errorCode = FileError::OK;
     OwnPtr<LocalErrorCallback> errorCallback = LocalErrorCallback::create(errorCode);
 
     OwnPtr<AsyncFileSystemCallbacks> callbacks = FileWriterBaseCallbacks::create(fileWriter, successCallback.release(), errorCallback.release());
     callbacks->setShouldBlockUntilCompletion(true);
 
     fileSystem()->createFileWriter(createFileSystemURL(fileEntry), fileWriter.get(), callbacks.release());
     if (errorCode != FileError::OK) {
         FileError::throwDOMException(exceptionState, errorCode);
-        return 0;
+        return nullptr;
     }
     return fileWriter.release();
 }
 
 }