third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/csharp/src/Google.Protobuf/WireFormat.cs

 #region Copyright notice and license
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
@@ skipping 84 matching lines @@
 
         /// <summary>
         /// Makes a tag value given a field number and wire type.
         /// </summary>
         public static uint MakeTag(int fieldNumber, WireType wireType)
         {
             return (uint) (fieldNumber << TagTypeBits) | (uint) wireType;
         }        
     }
 }