Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_coding/test/RTPFile.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 104 matching lines @@
 }
 
 bool RTPBuffer::EndOfFile() const {
   _queueRWLock->AcquireLockShared();
   bool eof = _rtpQueue.empty();
   _queueRWLock->ReleaseLockShared();
   return eof;
 }
 
 void RTPFile::Open(const char *filename, const char *mode) {
-  if ((_rtpFile = fopen(filename, mode)) == NULL) {
+  if ((_rtpFile = fopen(filename, mode)) == nullptr) {
     printf("Cannot write file %s.\n", filename);
     ADD_FAILURE() << "Unable to write file";
     exit(1);
   }
 }
 
 void RTPFile::Close() {
-  if (_rtpFile != NULL) {
+  if (_rtpFile != nullptr) {
     fclose(_rtpFile);
-    _rtpFile = NULL;
+    _rtpFile = nullptr;
   }
 }
 
 void RTPFile::WriteHeader() {
   // Write data in a format that NetEQ and RTP Play can parse
   fprintf(_rtpFile, "#!RTPencode%s\n", "1.0");
   uint32_t dummy_variable = 0;
   // should be converted to network endian format, but does not matter when 0
   EXPECT_EQ(1u, fwrite(&dummy_variable, 4, 1, _rtpFile));
   EXPECT_EQ(1u, fwrite(&dummy_variable, 4, 1, _rtpFile));
@@ skipping 72 matching lines @@
   }
   if (payloadSize < static_cast<size_t>((lengthBytes - 20))) {
     return 0;
   }
   lengthBytes -= 20;
   EXPECT_EQ(lengthBytes, fread(payloadData, 1, lengthBytes, _rtpFile));
   return lengthBytes;
 }
 
 }  // namespace webrtc