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

webrtc/common_audio/signal_processing/real_fft_unittest.cc

 /*
  *  Copyright (c) 2012 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 24 matching lines @@
 
 class RealFFTTest : public ::testing::Test {
  protected:
    RealFFTTest() {
      WebRtcSpl_Init();
    }
 };
 
 TEST_F(RealFFTTest, CreateFailsOnBadInput) {
   RealFFT* fft = WebRtcSpl_CreateRealFFT(11);
-  EXPECT_TRUE(fft == NULL);
+  EXPECT_TRUE(fft == nullptr);
   fft = WebRtcSpl_CreateRealFFT(-1);
-  EXPECT_TRUE(fft == NULL);
+  EXPECT_TRUE(fft == nullptr);
 }
 
 TEST_F(RealFFTTest, RealAndComplexMatch) {
   int i = 0;
   int j = 0;
   int16_t real_fft_time[kTimeDataLength] = {0};
   int16_t real_fft_freq[kFreqDataLength] = {0};
   // One common buffer for complex FFT's time and frequency data.
   int16_t complex_fft_buff[kComplexFftDataLength] = {0};
 
   // Prepare the inputs to forward FFT's.
   memcpy(real_fft_time, kRefData, sizeof(kRefData));
   for (i = 0, j = 0; i < kTimeDataLength; i += 1, j += 2) {
     complex_fft_buff[j] = kRefData[i];
     complex_fft_buff[j + 1] = 0;  // Insert zero's to imaginary parts.
   };
 
   // Create and run real forward FFT.
   RealFFT* fft = WebRtcSpl_CreateRealFFT(kOrder);
-  EXPECT_TRUE(fft != NULL);
+  EXPECT_TRUE(fft != nullptr);
   EXPECT_EQ(0, WebRtcSpl_RealForwardFFT(fft, real_fft_time, real_fft_freq));
 
   // Run complex forward FFT.
   WebRtcSpl_ComplexBitReverse(complex_fft_buff, kOrder);
   EXPECT_EQ(0, WebRtcSpl_ComplexFFT(complex_fft_buff, kOrder, 1));
 
   // Verify the results between complex and real forward FFT.
   for (i = 0; i < kFreqDataLength; i++) {
     EXPECT_EQ(real_fft_freq[i], complex_fft_buff[i]);
   }
@@ skipping 19 matching lines @@
   EXPECT_EQ(real_scale, complex_scale);
   for (i = 0, j = 0; i < kTimeDataLength; i += 1, j += 2) {
     EXPECT_LE(abs(real_fft_time[i] - complex_fft_buff[j]), 1);
   }
 
   WebRtcSpl_FreeRealFFT(fft);
 }
 
 }  // namespace
 }  // namespace webrtc