Replace NULL with nullptr in all C++ files.

webrtc/media/engine/webrtcvoiceengine.cc

 /*
  *  Copyright (c) 2004 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 140 matching lines @@
 
 bool IsCodec(const webrtc::CodecInst& codec, const char* ref_name) {
   return (_stricmp(codec.plname, ref_name) == 0);
 }
 
 bool FindCodec(const std::vector<AudioCodec>& codecs,
                const AudioCodec& codec,
                AudioCodec* found_codec) {
   for (const AudioCodec& c : codecs) {
     if (c.Matches(codec)) {
-      if (found_codec != NULL) {
+      if (found_codec != nullptr) {
         *found_codec = c;
       }
       return true;
     }
   }
   return false;
 }
 
 bool VerifyUniquePayloadTypes(const std::vector<AudioCodec>& codecs) {
   if (codecs.empty()) {
@@ skipping 2482 matching lines @@
   }
 
   return true;
 }
 
 void WebRtcVoiceMediaChannel::SetRawAudioSink(
     uint32_t ssrc,
     std::unique_ptr<webrtc::AudioSinkInterface> sink) {
   RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
   LOG(LS_VERBOSE) << "WebRtcVoiceMediaChannel::SetRawAudioSink: ssrc:" << ssrc
-                  << " " << (sink ? "(ptr)" : "NULL");
+                  << " " << (sink ? "(ptr)" : "null");
   if (ssrc == 0) {
     if (default_recv_ssrc_ != -1) {
       std::unique_ptr<webrtc::AudioSinkInterface> proxy_sink(
           sink ? new ProxySink(sink.get()) : nullptr);
       SetRawAudioSink(default_recv_ssrc_, std::move(proxy_sink));
     }
     default_sink_ = std::move(sink);
     return;
   }
   const auto it = recv_streams_.find(ssrc);
@@ skipping 23 matching lines @@
   RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
   const auto it = send_streams_.find(ssrc);
   if (it != send_streams_.end()) {
     return it->second->channel();
   }
   return -1;
 }
 }  // namespace cricket
 
 #endif  // HAVE_WEBRTC_VOICE