diff --git a/real_system_state.cc b/real_system_state.cc
index 44ff5fb..f093aad 100644
--- a/real_system_state.cc
+++ b/real_system_state.cc
@@ -41,7 +41,7 @@
     system_rebooted_ = true;
   }
 
-  p2p_manager_.reset(P2PManager::Construct(NULL, &prefs_, "cros_au",
+  p2p_manager_.reset(P2PManager::Construct(nullptr, &prefs_, "cros_au",
                                            kMaxP2PFilesToKeep));
 
   // Initialize the Update Manager using the default state factory.