[Chromoting] Use google:remoting namespace to export remoting specific error codes

remoting/protocol/name_value_map.h

 // 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.
 //
 // Helper functions that allow to map enum values to strings.
 
+#ifndef REMOTING_PROTOCOL_NAME_VALUE_MAP_H_
+#define REMOTING_PROTOCOL_NAME_VALUE_MAP_H_
+
 #include <stddef.h>
 
 #include "base/logging.h"
 
 namespace remoting {
 namespace protocol {
 
 template <typename T>
 struct NameMapElement {
   const T value;
@@ skipping 18 matching lines @@
     if (map[i].name == name) {
       *result = map[i].value;
       return true;
     }
   }
   return false;
 }
 
 }  // namespace protocol
 }  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_NAME_VALUE_MAP_H_