Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_processing/aecm/aecm_core_mips.cc

Index: webrtc/modules/audio_processing/aecm/aecm_core_mips.cc
diff --git a/webrtc/modules/audio_processing/aecm/aecm_core_mips.cc b/webrtc/modules/audio_processing/aecm/aecm_core_mips.cc
index 7d898f8cf49384a8c34c863b98357a901df0a787..946a4059f4f5878ba0f2cebf752118046cac542d 100644
--- a/webrtc/modules/audio_processing/aecm/aecm_core_mips.cc
+++ b/webrtc/modules/audio_processing/aecm/aecm_core_mips.cc
@@ -424,7 +424,7 @@ static void InverseFFTAndWindow(AecmCore* aecm,
   memcpy(aecm->dBufNoisy,
          aecm->dBufNoisy + PART_LEN,
          sizeof(int16_t) * PART_LEN);
-  if (nearendClean != NULL) {
+  if (nearendClean != nullptr) {
     memcpy(aecm->dBufClean,
            aecm->dBufClean + PART_LEN,
            sizeof(int16_t) * PART_LEN);
@@ -809,7 +809,7 @@ int WebRtcAecm_ProcessBlock(AecmCore* aecm,
   uint16_t dfaNoisy[PART_LEN1];
   uint16_t dfaClean[PART_LEN1];
   uint16_t* ptrDfaClean = dfaClean;
-  const uint16_t* far_spectrum_ptr = NULL;
+  const uint16_t* far_spectrum_ptr = nullptr;
 
   // 32 byte aligned buffers (with +8 or +16).
   int16_t fft_buf[PART_LEN4 + 2 + 16]; // +2 to make a loop safe.
@@ -865,7 +865,7 @@ int WebRtcAecm_ProcessBlock(AecmCore* aecm,
   memcpy(aecm->dBufNoisy + PART_LEN,
          nearendNoisy,
          sizeof(int16_t) * PART_LEN);
-  if (nearendClean != NULL) {
+  if (nearendClean != nullptr) {
     memcpy(aecm->dBufClean + PART_LEN,
            nearendClean,
            sizeof(int16_t) * PART_LEN);
@@ -887,7 +887,7 @@ int WebRtcAecm_ProcessBlock(AecmCore* aecm,
   aecm->dfaNoisyQDomainOld = aecm->dfaNoisyQDomain;
   aecm->dfaNoisyQDomain = (int16_t)zerosDBufNoisy;
 
-  if (nearendClean == NULL) {
+  if (nearendClean == nullptr) {
     ptrDfaClean = dfaNoisy;
     aecm->dfaCleanQDomainOld = aecm->dfaNoisyQDomainOld;
     aecm->dfaCleanQDomain = aecm->dfaNoisyQDomain;
@@ -933,7 +933,7 @@ int WebRtcAecm_ProcessBlock(AecmCore* aecm,
   far_spectrum_ptr = WebRtcAecm_AlignedFarend(aecm, &far_q, delay);
   zerosXBuf = (int16_t) far_q;
 
-  if (far_spectrum_ptr == NULL) {
+  if (far_spectrum_ptr == nullptr) {
     return -1;
   }