Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_coding/codecs/opus/opus_speed_test.cc

 /*
  *  Copyright (c) 2014 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 17 matching lines @@
   float DecodeABlock(const uint8_t* bit_stream, size_t encoded_bytes,
                      int16_t* out_data) override;
   WebRtcOpusEncInst* opus_encoder_;
   WebRtcOpusDecInst* opus_decoder_;
 };
 
 OpusSpeedTest::OpusSpeedTest()
     : AudioCodecSpeedTest(kOpusBlockDurationMs,
                           kOpusSamplingKhz,
                           kOpusSamplingKhz),
-      opus_encoder_(NULL),
-      opus_decoder_(NULL) {
-}
+      opus_encoder_(nullptr),
+      opus_decoder_(nullptr) {}
 
 void OpusSpeedTest::SetUp() {
   AudioCodecSpeedTest::SetUp();
   // If channels_ == 1, use Opus VOIP mode, otherwise, audio mode.
   int app = channels_ == 1 ? 0 : 1;
   /* Create encoder memory. */
   EXPECT_EQ(0, WebRtcOpus_EncoderCreate(&opus_encoder_, channels_, app));
   EXPECT_EQ(0, WebRtcOpus_DecoderCreate(&opus_decoder_, channels_));
   /* Set bitrate. */
   EXPECT_EQ(0, WebRtcOpus_SetBitRate(opus_encoder_, bit_rate_));
@@ skipping 61 matching lines @@
                             string("audio_coding/speech_mono_32_48kHz"),
                             string("pcm"), true),
      ::std::tr1::make_tuple(2, 64000,
                             string("audio_coding/music_stereo_48kHz"),
                             string("pcm"), true)};
 
 INSTANTIATE_TEST_CASE_P(AllTest, OpusSpeedTest,
                         ::testing::ValuesIn(param_set));
 
 }  // namespace webrtc