replace NULL->nullptr in src/remoting.

remoting/protocol/clipboard_echo_filter.cc

 // Copyright (c) 2012 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 "remoting/protocol/clipboard_echo_filter.h"
 
 #include "remoting/proto/event.pb.h"
 
 namespace remoting {
 namespace protocol {
 
 ClipboardEchoFilter::ClipboardEchoFilter()
-  : host_stub_(NULL),
-    client_stub_(NULL),
+  : host_stub_(nullptr),
+    client_stub_(nullptr),
     client_filter_(this),
     host_filter_(this) {
 }
 
 ClipboardEchoFilter::~ClipboardEchoFilter() {
 }
 
 void ClipboardEchoFilter::set_client_stub(ClipboardStub* client_stub) {
   client_stub_ = client_stub;
 }
@@ skipping 44 matching lines @@
     ClipboardEchoFilter* filter) : filter_(filter) {
 }
 
 void ClipboardEchoFilter::HostFilter::InjectClipboardEvent(
     const ClipboardEvent& event) {
   filter_->InjectClipboardEventToHost(event);
 }
 
 }  // namespace protocol
 }  // namespace remoting