QUIC - (no behavior change) s/NULL/nullptr/g in .../quic/...

net/quic/crypto/crypto_utils.cc

Index: net/quic/crypto/crypto_utils.cc
diff --git a/net/quic/crypto/crypto_utils.cc b/net/quic/crypto/crypto_utils.cc
index 041c284b935871e26ed1dcea28ca13ec3cd09aea..7e0ab75bdd9483aad905cdd8f83410395f6230b1 100644
--- a/net/quic/crypto/crypto_utils.cc
+++ b/net/quic/crypto/crypto_utils.cc
@@ -91,7 +91,7 @@ bool CryptoUtils::DeriveKeys(StringPiece premaster_secret,
   size_t key_bytes = crypters->encrypter->GetKeySize();
   size_t nonce_prefix_bytes = crypters->encrypter->GetNoncePrefixSize();
   size_t subkey_secret_bytes =
-      subkey_secret == NULL ? 0 : premaster_secret.length();
+      subkey_secret == nullptr ? 0 : premaster_secret.length();
 
   StringPiece nonce = client_nonce;
   string nonce_storage;
@@ -117,7 +117,7 @@ bool CryptoUtils::DeriveKeys(StringPiece premaster_secret,
       return false;
     }
   }
-  if (subkey_secret != NULL) {
+  if (subkey_secret != nullptr) {
     hkdf.subkey_secret().CopyToString(subkey_secret);
   }