Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_coding/acm2/audio_coding_module_unittest.cc

 /*
  *  Copyright (c) 2014 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 1108 matching lines @@
   // false.
   bool SetUpSender() {
     const std::string input_file_name =
         webrtc::test::ResourcePath("audio_coding/testfile32kHz", "pcm");
     // Note that |audio_source_| will loop forever. The test duration is set
     // explicitly by |kTestDurationMs|.
     audio_source_.reset(new test::InputAudioFile(input_file_name));
     static const int kSourceRateHz = 32000;
     send_test_.reset(new test::AcmSendTestOldApi(
         audio_source_.get(), kSourceRateHz, kTestDurationMs));
-    return send_test_.get() != NULL;
+    return send_test_.get() != nullptr;
   }
 
   // Registers a send codec in the test::AcmSendTest object. Returns true on
   // success, false on failure.
   bool RegisterSendCodec(const char* payload_name,
                          int sampling_freq_hz,
                          int channels,
                          int payload_type,
                          int frame_size_samples,
                          int frame_size_rtp_timestamps) {
@@ skipping 57 matching lines @@
     EXPECT_EQ(expected_packets, packet_count_);
 
     // Delete the output file.
     remove(output_file_name.c_str());
   }
 
   // Inherited from test::PacketSource.
   std::unique_ptr<test::Packet> NextPacket() override {
     auto packet = send_test_->NextPacket();
     if (!packet)
-      return NULL;
+      return nullptr;
 
     VerifyPacket(packet.get());
     // TODO(henrik.lundin) Save the packet to file as well.
 
     // Pass it on to the caller. The caller becomes the owner of |packet|.
     return packet;
   }
 
   // Verifies the packet.
   void VerifyPacket(const test::Packet* packet) {
@@ skipping 564 matching lines @@
     remove(output_file_name.c_str());
   }
 
   // Inherited from test::PacketSource.
   std::unique_ptr<test::Packet> NextPacket() override {
     // Check if it is time to terminate the test. The packet source is of type
     // ConstantPcmPacketSource, which is infinite, so we must end the test
     // "manually".
     if (num_packets_++ > kTestNumPackets) {
       EXPECT_TRUE(has_toggled_);
-      return NULL;  // Test ended.
+      return nullptr;  // Test ended.
     }
 
     // Get the next packet from the source.
     return packet_source_.NextPacket();
   }
 
   // Inherited from test::AudioSink.
   bool WriteArray(const int16_t* audio, size_t num_samples) override {
     // Skip checking the first output frame, since it has a number of zeros
     // due to how NetEq is initialized.
@@ skipping 36 matching lines @@
   Run(16000, 8000, 1000);
 }
 
 TEST_F(AcmSwitchingOutputFrequencyOldApi, Toggle8KhzTo16Khz) {
   Run(8000, 16000, 1000);
 }
 
 #endif
 
 }  // namespace webrtc