Replace NULL with nullptr in all C++ files.

webrtc/pc/dtmfsender_unittest.cc

 /*
  *  Copyright 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 100 matching lines @@
  private:
   bool can_insert_ = false;
   std::vector<DtmfInfo> dtmf_info_queue_;
   int64_t last_insert_dtmf_call_;
   sigslot::signal0<> SignalDestroyed;
 };
 
 class DtmfSenderTest : public testing::Test {
  protected:
   DtmfSenderTest()
-      : track_(AudioTrack::Create(kTestAudioLabel, NULL)),
+      : track_(AudioTrack::Create(kTestAudioLabel, nullptr)),
         observer_(new rtc::RefCountedObject<FakeDtmfObserver>()),
         provider_(new FakeDtmfProvider()) {
     provider_->SetCanInsertDtmf(true);
     dtmf_ = DtmfSender::Create(track_, rtc::Thread::Current(),
                                provider_.get());
     dtmf_->RegisterObserver(observer_.get());
   }
 
   ~DtmfSenderTest() {
     if (dtmf_.get()) {
@@ skipping 144 matching lines @@
 
 TEST_F(DtmfSenderTest, InsertDtmfWhileSenderIsDeleted) {
   std::string tones = "@1%a&*$";
   int duration = 100;
   int inter_tone_gap = 50;
   EXPECT_TRUE(dtmf_->InsertDtmf(tones, duration, inter_tone_gap));
   // Wait until the first tone got sent.
   EXPECT_TRUE_SIMULATED_WAIT(observer_->tones().size() == 1, kMaxWaitMs,
                              fake_clock_);
   // Delete the sender.
-  dtmf_ = NULL;
+  dtmf_ = nullptr;
   // The queue should be discontinued so no more tone callbacks.
   SIMULATED_WAIT(false, 200, fake_clock_);
   EXPECT_EQ(1U, observer_->tones().size());
 }
 
 TEST_F(DtmfSenderTest, InsertEmptyTonesToCancelPreviousTask) {
   std::string tones1 = "12";
   std::string tones2 = "";
   int duration = 100;
   int inter_tone_gap = 50;
@@ skipping 35 matching lines @@
   std::string tones = "3,4";
   int duration = 100;
   int inter_tone_gap = 50;
 
   EXPECT_FALSE(dtmf_->InsertDtmf(tones, 6001, inter_tone_gap));
   EXPECT_FALSE(dtmf_->InsertDtmf(tones, 69, inter_tone_gap));
   EXPECT_FALSE(dtmf_->InsertDtmf(tones, duration, 49));
 
   EXPECT_TRUE(dtmf_->InsertDtmf(tones, duration, inter_tone_gap));
 }