Replace NULL with nullptr.

extensions/browser/api/cast_channel/cast_auth_util_openssl.cc

Index: extensions/browser/api/cast_channel/cast_auth_util_openssl.cc
diff --git a/extensions/browser/api/cast_channel/cast_auth_util_openssl.cc b/extensions/browser/api/cast_channel/cast_auth_util_openssl.cc
index b662840b6fc8d0e916f812217aeee9324edc0492..f3a4e1d52c0197370105db4056df25c93ceaaba5 100644
--- a/extensions/browser/api/cast_channel/cast_auth_util_openssl.cc
+++ b/extensions/browser/api/cast_channel/cast_auth_util_openssl.cc
@@ -62,7 +62,7 @@ AuthResult VerifyCredentials(const AuthResponse& response,
       reinterpret_cast<const uint8_t*>(ca_public_key_bytes.data());
   const uint8_t* ca_public_key_end = ca_ptr + ca_public_key_bytes.size();
   crypto::ScopedRSA ca_public_key_rsa(
-      d2i_RSAPublicKey(NULL, &ca_ptr, ca_public_key_bytes.size()));
+      d2i_RSAPublicKey(nullptr, &ca_ptr, ca_public_key_bytes.size()));
   if (!ca_public_key_rsa || ca_ptr != ca_public_key_end) {
     LOG(ERROR) << "Failed to import trusted public key.";
     return AuthResult::CreateWithParseError(
@@ -84,9 +84,8 @@ AuthResult VerifyCredentials(const AuthResponse& response,
   const uint8_t* client_cert_end =
       client_cert_ptr +
       response.client_auth_certificate().size();
-  const ScopedX509 client_cert(
-      d2i_X509(NULL, &client_cert_ptr,
-               response.client_auth_certificate().size()));
+  const ScopedX509 client_cert(d2i_X509(
+      nullptr, &client_cert_ptr, response.client_auth_certificate().size()));
   if (!client_cert || client_cert_ptr != client_cert_end) {
     LOG(ERROR) << "Failed to parse certificate.";
     return AuthResult::CreateWithParseError(
@@ -118,7 +117,7 @@ AuthResult VerifyCredentials(const AuthResponse& response,
   // key.
   const crypto::ScopedEVP_MD_CTX ctx(EVP_MD_CTX_create());
   if (!ctx ||
-      !EVP_DigestVerifyInit(ctx.get(), NULL, EVP_sha1(), NULL,
+      !EVP_DigestVerifyInit(ctx.get(), nullptr, EVP_sha1(), nullptr,
                             client_public_key.get()) ||
       !EVP_DigestVerifyUpdate(ctx.get(), peer_cert.data(), peer_cert.size())) {
     return AuthResult::CreateWithParseError(