Replace NULL with nullptr or null in webrtc/audio/ and common_audio/.

webrtc/audio/audio_send_stream_unittest.cc

 /*
  *  Copyright (c) 2015 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 258 matching lines @@
   config.send_codec_spec.cng_payload_type = 42;
   config.send_codec_spec.cng_plfreq = 56;
   config.send_codec_spec.min_ptime_ms = 20;
   config.send_codec_spec.max_ptime_ms = 60;
   config.send_codec_spec.codec_inst = kIsacCodec;
   config.rtp.extensions.push_back(
       RtpExtension(RtpExtension::kAudioLevelUri, kAudioLevelId));
   EXPECT_EQ(
       "{rtp: {ssrc: 1234, extensions: [{uri: "
       "urn:ietf:params:rtp-hdrext:ssrc-audio-level, id: 2}], nack: "
-      "{rtp_history_ms: 0}, c_name: foo_name}, send_transport: nullptr, "
+      "{rtp_history_ms: 0}, c_name: foo_name}, send_transport: null, "
       "voe_channel_id: 1, min_bitrate_bps: 12000, max_bitrate_bps: 34000, "
       "send_codec_spec: {nack_enabled: true, transport_cc_enabled: false, "
       "enable_codec_fec: true, enable_opus_dtx: false, opus_max_playback_rate: "
       "32000, cng_payload_type: 42, cng_plfreq: 56, min_ptime: 20, max_ptime: "
       "60, codec_inst: {pltype: 103, plname: \"isac\", plfreq: 16000, pacsize: "
       "320, channels: 1, rate: 32000}}}",
       config.ToString());
 }
 
 TEST(AudioSendStreamTest, ConstructDestruct) {
@@ skipping 169 matching lines @@
   internal::AudioSendStream send_stream(
       helper.config(), helper.audio_state(), helper.worker_queue(),
       helper.packet_router(), helper.congestion_controller(),
       helper.bitrate_allocator(), helper.event_log(), helper.rtcp_rtt_stats());
   EXPECT_CALL(*helper.channel_proxy(), SetBitrate(_, 5000));
   send_stream.OnBitrateUpdated(50000, 0.0, 50, 5000);
 }
 
 }  // namespace test
 }  // namespace webrtc