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

mojo/system/local_message_pipe_endpoint.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/system/local_message_pipe_endpoint.h"
 
 #include <string.h>
 
 #include "base/logging.h"
 #include "mojo/system/dispatcher.h"
@@ skipping 90 matching lines @@
         dispatchers->swap(*queued_dispatchers);
       } else {
         enough_space = false;
       }
     }
   } else {
     if (num_dispatchers)
       *num_dispatchers = 0;
   }
 
-  message = NULL;
+  message = nullptr;
 
   if (enough_space || (flags & MOJO_READ_MESSAGE_FLAG_MAY_DISCARD)) {
     message_queue_.DiscardMessage();
 
     // Now it's empty, thus no longer readable.
     if (message_queue_.IsEmpty()) {
       // It's currently not possible to wait for non-readability, but we should
       // do the state change anyway.
       waiter_list_.AwakeWaitersForStateChange(GetHandleSignalsState());
     }
@@ skipping 45 matching lines @@
 void LocalMessagePipeEndpoint::RemoveWaiter(Waiter* waiter,
                                             HandleSignalsState* signals_state) {
   DCHECK(is_open_);
   waiter_list_.RemoveWaiter(waiter);
   if (signals_state)
     *signals_state = GetHandleSignalsState();
 }
 
 }  // namespace system
 }  // namespace mojo