Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_coding/test/PCMFile.cc

Index: webrtc/modules/audio_coding/test/PCMFile.cc
diff --git a/webrtc/modules/audio_coding/test/PCMFile.cc b/webrtc/modules/audio_coding/test/PCMFile.cc
index 5d2d8183222820a2e26b87263ac20197b948bc0c..33d523c6997572cd25a10ab0c24630d254591638 100644
--- a/webrtc/modules/audio_coding/test/PCMFile.cc
+++ b/webrtc/modules/audio_coding/test/PCMFile.cc
@@ -22,7 +22,7 @@ namespace webrtc {
 #define MAX_FILE_NAME_LENGTH_BYTE 500
 
 PCMFile::PCMFile()
-    : pcm_file_(NULL),
+    : pcm_file_(nullptr),
       samples_10ms_(160),
       frequency_(16000),
       end_of_file_(false),
@@ -35,7 +35,7 @@ PCMFile::PCMFile()
 }
 
 PCMFile::PCMFile(uint32_t timestamp)
-    : pcm_file_(NULL),
+    : pcm_file_(nullptr),
       samples_10ms_(160),
       frequency_(16000),
       end_of_file_(false),
@@ -56,7 +56,7 @@ int16_t PCMFile::ChooseFile(std::string* file_name, int16_t max_len,
                             uint16_t* frequency_hz) {
   char tmp_name[MAX_FILE_NAME_LENGTH_BYTE];
 
-  EXPECT_TRUE(fgets(tmp_name, MAX_FILE_NAME_LENGTH_BYTE, stdin) != NULL);
+  EXPECT_TRUE(fgets(tmp_name, MAX_FILE_NAME_LENGTH_BYTE, stdin) != nullptr);
   tmp_name[MAX_FILE_NAME_LENGTH_BYTE - 1] = '\0';
   int16_t n = 0;
 
@@ -90,7 +90,7 @@ int16_t PCMFile::ChooseFile(std::string* file_name, int16_t max_len,
   }
   printf("Enter the sampling frequency (in Hz) of the above file [%u]: ",
          *frequency_hz);
-  EXPECT_TRUE(fgets(tmp_name, 10, stdin) != NULL);
+  EXPECT_TRUE(fgets(tmp_name, 10, stdin) != nullptr);
   uint16_t tmp_frequency = (uint16_t) atoi(tmp_name);
   if (tmp_frequency > 0) {
     *frequency_hz = tmp_frequency;
@@ -100,7 +100,7 @@ int16_t PCMFile::ChooseFile(std::string* file_name, int16_t max_len,
 
 void PCMFile::Open(const std::string& file_name, uint16_t frequency,
                    const char* mode, bool auto_rewind) {
-  if ((pcm_file_ = fopen(file_name.c_str(), mode)) == NULL) {
+  if ((pcm_file_ = fopen(file_name.c_str(), mode)) == nullptr) {
     printf("Cannot open file %s.\n", file_name.c_str());
     ADD_FAILURE() << "Unable to read file";
   }
@@ -190,7 +190,7 @@ void PCMFile::Write10MsData(int16_t* playout_buffer, size_t length_smpls) {
 
 void PCMFile::Close() {
   fclose(pcm_file_);
-  pcm_file_ = NULL;
+  pcm_file_ = nullptr;
   blocks_read_ = 0;
 }