Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_coding/acm2/acm_receiver_unittest.cc

Index: webrtc/modules/audio_coding/acm2/acm_receiver_unittest.cc
diff --git a/webrtc/modules/audio_coding/acm2/acm_receiver_unittest.cc b/webrtc/modules/audio_coding/acm2/acm_receiver_unittest.cc
index d5a63ccd49ce2df184ae7a66cf673751a02d009c..13541b9748b14692dafd24011e1126d7031d45d4 100644
--- a/webrtc/modules/audio_coding/acm2/acm_receiver_unittest.cc
+++ b/webrtc/modules/audio_coding/acm2/acm_receiver_unittest.cc
@@ -67,8 +67,8 @@ class AcmReceiverTestOldApi : public AudioPacketizationCallback,
   void SetUp() override {
     acm_.reset(AudioCodingModule::Create(config_));
     receiver_.reset(new AcmReceiver(config_));
-    ASSERT_TRUE(receiver_.get() != NULL);
-    ASSERT_TRUE(acm_.get() != NULL);
+    ASSERT_TRUE(receiver_.get() != nullptr);
+    ASSERT_TRUE(acm_.get() != nullptr);
     codecs_ = RentACodec::Database();
 
     acm_->InitializeReceiver();
@@ -174,9 +174,9 @@ TEST_F(AcmReceiverTestOldApi, MAYBE_AddCodecGetCodec) {
   // Add codec.
   for (size_t n = 0; n < codecs_.size(); ++n) {
     if (n & 0x1) {  // Just add codecs with odd index.
-      EXPECT_EQ(
-          0, receiver_->AddCodec(n, codecs_[n].pltype, codecs_[n].channels,
-                                 codecs_[n].plfreq, NULL, codecs_[n].plname));
+      EXPECT_EQ(0, receiver_->AddCodec(n, codecs_[n].pltype,
+                                       codecs_[n].channels, codecs_[n].plfreq,
+                                       nullptr, codecs_[n].plname));
     }
   }
   // Get codec and compare.
@@ -211,7 +211,7 @@ TEST_F(AcmReceiverTestOldApi, MAYBE_AddCodecChangePayloadType) {
                                    codec1.inst.channels, codec1.inst.plfreq,
                                    nullptr, codec1.inst.plname));
   EXPECT_EQ(0, receiver_->AddCodec(codec1.id, codec2.pltype, codec2.channels,
-                                   codec2.plfreq, NULL, codec2.plname));
+                                   codec2.plfreq, nullptr, codec2.plname));
 
   // Both payload types should exist.
   EXPECT_EQ(0,