third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/csharp/src/Google.Protobuf/CodedOutputStream.ComputeSize.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 284 matching lines @@
 
         /// <summary>
         /// Computes the number of bytes that would be needed to encode a tag.
         /// </summary>
         public static int ComputeTagSize(int fieldNumber)
         {
             return ComputeRawVarint32Size(WireFormat.MakeTag(fieldNumber, 0));
         }
     }
 }