replace NULL->nullptr in src/remoting.

remoting/protocol/v2_authenticator.cc

Index: remoting/protocol/v2_authenticator.cc
diff --git a/remoting/protocol/v2_authenticator.cc b/remoting/protocol/v2_authenticator.cc
index 37652a2c40737acf37c6c900af1cf8a68ddf7937..f37e74fa354a6e517fb5eb58b63b42c0a54efe47 100644
--- a/remoting/protocol/v2_authenticator.cc
+++ b/remoting/protocol/v2_authenticator.cc
@@ -31,7 +31,7 @@ const buzz::StaticQName kCertificateTag = { kChromotingXmlNamespace,
 
 // static
 bool V2Authenticator::IsEkeMessage(const buzz::XmlElement* message) {
-  return message->FirstNamed(kEkeTag) != NULL;
+  return message->FirstNamed(kEkeTag) != nullptr;
 }
 
 // static
@@ -200,7 +200,7 @@ V2Authenticator::CreateChannelAuthenticator() const {
 }
 
 bool V2Authenticator::is_host_side() const {
-  return local_key_pair_.get() != NULL;
+  return local_key_pair_.get() != nullptr;
 }
 
 }  // namespace protocol