replace NULL->nullptr in src/remoting.

remoting/host/it2me/it2me_native_messaging_host_main.cc

Index: remoting/host/it2me/it2me_native_messaging_host_main.cc
diff --git a/remoting/host/it2me/it2me_native_messaging_host_main.cc b/remoting/host/it2me/it2me_native_messaging_host_main.cc
index cf30a87f449df2a239268701cea0fa489b65e976..a89ee5296ee47c76b8609785904ba811a47c6053 100644
--- a/remoting/host/it2me/it2me_native_messaging_host_main.cc
+++ b/remoting/host/it2me/it2me_native_messaging_host_main.cc
@@ -71,9 +71,9 @@ int StartIt2MeNativeMessagingHost() {
   XInitThreads();
 
   // Required for any calls into GTK functions, such as the Disconnect and
-  // Continue windows. Calling with NULL arguments because we don't have
+  // Continue windows. Calling with nullptr arguments because we don't have
   // any command line arguments for gtk to consume.
-  gtk_init(NULL, NULL);
+  gtk_init(nullptr, nullptr);
 #endif  // OS_LINUX
 
   // Enable support for SSL server sockets, which must be done while still
@@ -96,8 +96,8 @@ int StartIt2MeNativeMessagingHost() {
   // the STD* handles at startup. So any LoadLibrary request can potentially
   // be blocked. To prevent that from happening we close STDIN and STDOUT
   // handles as soon as we retrieve the corresponding file handles.
-  SetStdHandle(STD_INPUT_HANDLE, NULL);
-  SetStdHandle(STD_OUTPUT_HANDLE, NULL);
+  SetStdHandle(STD_INPUT_HANDLE, nullptr);
+  SetStdHandle(STD_OUTPUT_HANDLE, nullptr);
 #elif defined(OS_POSIX)
   // The files are automatically closed.
   base::File read_file(STDIN_FILENO);