Mojo: NULL -> nullptr in mojo/system and mojo/embedder.

mojo/system/message_pipe_dispatcher.cc

Index: mojo/system/message_pipe_dispatcher.cc
diff --git a/mojo/system/message_pipe_dispatcher.cc b/mojo/system/message_pipe_dispatcher.cc
index 94aceb0e054c641d57036bea705114720b9ef2f2..abe0ecb98f99ed87482313719e1df39b67586c7e 100644
--- a/mojo/system/message_pipe_dispatcher.cc
+++ b/mojo/system/message_pipe_dispatcher.cc
@@ -162,7 +162,7 @@ void MessagePipeDispatcher::CancelAllWaitersNoLock() {
 void MessagePipeDispatcher::CloseImplNoLock() {
   lock().AssertAcquired();
   message_pipe_->Close(port_);
-  message_pipe_ = NULL;
+  message_pipe_ = nullptr;
   port_ = kInvalidPort;
 }
 
@@ -176,7 +176,7 @@ MessagePipeDispatcher::CreateEquivalentDispatcherAndCloseImplNoLock() {
   scoped_refptr<MessagePipeDispatcher> rv =
       new MessagePipeDispatcher(kDefaultCreateOptions);
   rv->Init(message_pipe_, port_);
-  message_pipe_ = NULL;
+  message_pipe_ = nullptr;
   port_ = kInvalidPort;
   return scoped_refptr<Dispatcher>(rv.get());
 }
@@ -265,7 +265,7 @@ bool MessagePipeDispatcher::EndSerializeAndCloseImplNoLock(
   static_cast<SerializedMessagePipeDispatcher*>(destination)->endpoint_id =
       endpoint_id;
 
-  message_pipe_ = NULL;
+  message_pipe_ = nullptr;
   port_ = kInvalidPort;
 
   *actual_size = sizeof(SerializedMessagePipeDispatcher);