replace NULL->nullptr in src/remoting.

remoting/host/audio_capturer_linux.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/audio_capturer_linux.h"
 
 #include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "remoting/proto/audio.pb.h"
@@ skipping 58 matching lines @@
   scoped_ptr<AudioPacket> packet(new AudioPacket());
   packet->add_data(data->data());
   packet->set_encoding(AudioPacket::ENCODING_RAW);
   packet->set_sampling_rate(AudioPipeReader::kSamplingRate);
   packet->set_bytes_per_sample(AudioPipeReader::kBytesPerSample);
   packet->set_channels(AudioPipeReader::kChannels);
   callback_.Run(packet.Pass());
 }
 
 bool AudioCapturer::IsSupported() {
-  return g_pulseaudio_pipe_sink_reader.Get().get() != NULL;
+  return g_pulseaudio_pipe_sink_reader.Get().get() != nullptr;
 }
 
 scoped_ptr<AudioCapturer> AudioCapturer::Create() {
   scoped_refptr<AudioPipeReader> reader =
       g_pulseaudio_pipe_sink_reader.Get();
   if (!reader.get())
     return nullptr;
   return make_scoped_ptr(new AudioCapturerLinux(reader));
 }
 
 }  // namespace remoting