Replace NULL with nullptr in all C++ files.

webrtc/modules/rtp_rtcp/source/receive_statistics_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/receive_statistics_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/receive_statistics_unittest.cc b/webrtc/modules/rtp_rtcp/source/receive_statistics_unittest.cc
index 97f6fa3bdca9628a94fae739daec0e02d602aba4..50c26a94a4bc16c5cb3cbd64d85de549b167d7ba 100644
--- a/webrtc/modules/rtp_rtcp/source/receive_statistics_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/receive_statistics_unittest.cc
@@ -55,7 +55,7 @@ TEST_F(ReceiveStatisticsTest, TwoIncomingSsrcs) {
 
   StreamStatistician* statistician =
       receive_statistics_->GetStatistician(kSsrc1);
-  ASSERT_TRUE(statistician != NULL);
+  ASSERT_TRUE(statistician != nullptr);
   EXPECT_GT(statistician->BitrateReceived(), 0u);
   size_t bytes_received = 0;
   uint32_t packets_received = 0;
@@ -65,7 +65,7 @@ TEST_F(ReceiveStatisticsTest, TwoIncomingSsrcs) {
 
   statistician =
       receive_statistics_->GetStatistician(kSsrc2);
-  ASSERT_TRUE(statistician != NULL);
+  ASSERT_TRUE(statistician != nullptr);
   EXPECT_GT(statistician->BitrateReceived(), 0u);
   statistician->GetDataCounters(&bytes_received, &packets_received);
   EXPECT_EQ(600u, bytes_received);
@@ -125,7 +125,7 @@ TEST_F(ReceiveStatisticsTest, ActiveStatisticians) {
   EXPECT_EQ(1u, statisticians.size());
   StreamStatistician* statistician =
       receive_statistics_->GetStatistician(kSsrc1);
-  ASSERT_TRUE(statistician != NULL);
+  ASSERT_TRUE(statistician != nullptr);
   size_t bytes_received = 0;
   uint32_t packets_received = 0;
   statistician->GetDataCounters(&bytes_received, &packets_received);
@@ -137,7 +137,7 @@ TEST_F(ReceiveStatisticsTest, GetReceiveStreamDataCounters) {
   receive_statistics_->IncomingPacket(header1_, kPacketSize1, false);
   StreamStatistician* statistician =
       receive_statistics_->GetStatistician(kSsrc1);
-  ASSERT_TRUE(statistician != NULL);
+  ASSERT_TRUE(statistician != nullptr);
 
   StreamDataCounters counters;
   statistician->GetReceiveStreamDataCounters(&counters);
@@ -211,7 +211,7 @@ TEST_F(ReceiveStatisticsTest, RtcpCallbacks) {
   EXPECT_EQ(5u, statistics.extended_max_sequence_number);
   EXPECT_EQ(4u, statistics.jitter);
 
-  receive_statistics_->RegisterRtcpStatisticsCallback(NULL);
+  receive_statistics_->RegisterRtcpStatisticsCallback(nullptr);
 
   // Add some more data.
   header1_.sequenceNumber = 1;
@@ -340,7 +340,7 @@ TEST_F(ReceiveStatisticsTest, RtpCallbacks) {
   expected.fec.packets = 1;
   callback.Matches(5, kSsrc1, expected);
 
-  receive_statistics_->RegisterRtpStatisticsCallback(NULL);
+  receive_statistics_->RegisterRtpStatisticsCallback(nullptr);
 
   // New stats, but callback should not be called.
   ++header1_.sequenceNumber;