Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_coding/neteq/timestamp_scaler_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 282 matching lines @@
     internal_timestamp += kStep;
   }
 
   EXPECT_CALL(db, Die());  // Called when database object is deleted.
 }
 
 TEST(TimestampScaler, Failures) {
   static const uint8_t kRtpPayloadType = 17;
   MockDecoderDatabase db;
   EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
-      .WillOnce(ReturnNull());  // Return NULL to indicate unknown payload type.
+      .WillOnce(
+          ReturnNull());  // Return nullptr to indicate unknown payload type.
 
   TimestampScaler scaler(db);
   uint32_t timestamp = 4711;  // Some number.
   EXPECT_EQ(timestamp, scaler.ToInternal(timestamp, kRtpPayloadType));
 
-  Packet* packet = NULL;
+  Packet* packet = nullptr;
   scaler.ToInternal(packet);  // Should not crash. That's all we can test.
 
   EXPECT_CALL(db, Die());  // Called when database object is deleted.
 }
 
 }  // namespace webrtc