Replace NULL with nullptr in all C++ files.

webrtc/p2p/base/stunserver_unittest.cc

Index: webrtc/p2p/base/stunserver_unittest.cc
diff --git a/webrtc/p2p/base/stunserver_unittest.cc b/webrtc/p2p/base/stunserver_unittest.cc
index 553ad8a0a7492211fa2bdb7bc0730bfa762975a8..dd8bd2866581e371fea7d0e52c4e49ed162ea224 100644
--- a/webrtc/p2p/base/stunserver_unittest.cc
+++ b/webrtc/p2p/base/stunserver_unittest.cc
@@ -51,7 +51,7 @@ class StunServerTest : public testing::Test {
     return(client_->CheckNoPacket());
   }
   StunMessage* Receive() {
-    StunMessage* msg = NULL;
+    StunMessage* msg = nullptr;
     rtc::TestClient::Packet* packet =
         client_->NextPacket(rtc::TestClient::kTimeoutMs);
     if (packet) {
@@ -82,13 +82,13 @@ TEST_F(StunServerTest, TestGood) {
   Send(req);
 
   StunMessage* msg = Receive();
-  ASSERT_TRUE(msg != NULL);
+  ASSERT_TRUE(msg != nullptr);
   EXPECT_EQ(STUN_BINDING_RESPONSE, msg->type());
   EXPECT_EQ(req.transaction_id(), msg->transaction_id());
 
   const StunAddressAttribute* mapped_addr =
       msg->GetAddress(STUN_ATTR_MAPPED_ADDRESS);
-  EXPECT_TRUE(mapped_addr != NULL);
+  EXPECT_TRUE(mapped_addr != nullptr);
   EXPECT_EQ(1, mapped_addr->family());
   EXPECT_EQ(client_addr.port(), mapped_addr->port());
   if (mapped_addr->ipaddr() != client_addr.ipaddr()) {