Replace NULL with nullptr in all C++ files.

webrtc/modules/video_coding/video_receiver_unittest.cc

Index: webrtc/modules/video_coding/video_receiver_unittest.cc
diff --git a/webrtc/modules/video_coding/video_receiver_unittest.cc b/webrtc/modules/video_coding/video_receiver_unittest.cc
index 9cac45b86b380330072f22f1811e4c9f4b65ee16..83a33c6b6c1336a8f4c05c664eb6650de1e33ed6 100644
--- a/webrtc/modules/video_coding/video_receiver_unittest.cc
+++ b/webrtc/modules/video_coding/video_receiver_unittest.cc
@@ -49,7 +49,7 @@ class TestVideoReceiver : public ::testing::Test {
 
   void InsertAndVerifyPaddingFrame(const uint8_t* payload,
                                    WebRtcRTPHeader* header) {
-    ASSERT_TRUE(header != NULL);
+    ASSERT_TRUE(header != nullptr);
     for (int j = 0; j < 5; ++j) {
       // Padding only packets are passed to the VCM with payload size 0.
       EXPECT_EQ(0, receiver_->IncomingPacket(payload, 0, *header));
@@ -63,7 +63,7 @@ class TestVideoReceiver : public ::testing::Test {
   void InsertAndVerifyDecodableFrame(const uint8_t* payload,
                                      size_t length,
                                      WebRtcRTPHeader* header) {
-    ASSERT_TRUE(header != NULL);
+    ASSERT_TRUE(header != nullptr);
     EXPECT_EQ(0, receiver_->IncomingPacket(payload, length, *header));
     ++header->header.sequenceNumber;
     EXPECT_CALL(packet_request_callback_, ResendPackets(_, _)).Times(0);