replace NULL->nullptr in src/remoting.

remoting/protocol/authenticator.h

Index: remoting/protocol/authenticator.h
diff --git a/remoting/protocol/authenticator.h b/remoting/protocol/authenticator.h
index 12109892472375e11291079646101cdd45190ddc..5ed10d862bcd8f4349793921c04b9d5e91a483fc 100644
--- a/remoting/protocol/authenticator.h
+++ b/remoting/protocol/authenticator.h
@@ -79,7 +79,7 @@ class Authenticator {
   static scoped_ptr<buzz::XmlElement> CreateEmptyAuthenticatorMessage();
 
   // Finds Authenticator message among child elements of |message|, or
-  // returns NULL otherwise.
+  // returns nullptr otherwise.
   static const buzz::XmlElement* FindAuthenticatorMessage(
       const buzz::XmlElement* message);
 
@@ -125,7 +125,7 @@ class AuthenticatorFactory {
   // authenticator for the new session. |first_message| specifies
   // authentication part of the session-initiate stanza so that
   // appropriate type of Authenticator can be chosen for the session
-  // (useful when multiple authenticators is supported). Returns NULL
+  // (useful when multiple authenticators is supported). Returns nullptr
   // if the |first_message| is invalid and the session should be
   // rejected. ProcessMessage() should be called with |first_message|
   // for the result of this method.