Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/unittest_custom_options.proto

 // 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
 // notice, this list of conditions and the following disclaimer.
@@ skipping 51 matching lines @@
   optional int32 message_opt1 = 7739036;
 }
 
 extend google.protobuf.FieldOptions {
   optional fixed64 field_opt1 = 7740936;
   // This is useful for testing that we correctly register default values for
   // extension options.
   optional int32 field_opt2 = 7753913 [default=42];
 }
 
-extend google.protobuf.OneofOptions {
-  optional int32 oneof_opt1 = 7740111;
-}
-
 extend google.protobuf.EnumOptions {
   optional sfixed32 enum_opt1 = 7753576;
 }
 
 extend google.protobuf.EnumValueOptions {
   optional int32 enum_value_opt1 = 1560678;
 }
 
 extend google.protobuf.ServiceOptions {
   optional sint64 service_opt1 = 7887650;
@@ skipping 11 matching lines @@
 // A test message with custom options at all possible locations (and also some
 // regular options, to make sure they interact nicely).
 message TestMessageWithCustomOptions {
   option message_set_wire_format = false;
 
   option (message_opt1) = -56;
 
   optional string field1 = 1 [ctype=CORD,
                               (field_opt1)=8765432109];
 
-  oneof AnOneof {
-    option (oneof_opt1) = -99;
-    int32 oneof_field = 2;
-  }
-
   enum AnEnum {
     option (enum_opt1) = -789;
 
     ANENUM_VAL1 = 1;
     ANENUM_VAL2 = 2 [(enum_value_opt1) = 123];
   }
 }
 
 
 // A test RPC service with custom options at all possible locations (and also
@@ skipping 299 matching lines @@
 }
 
 extend google.protobuf.MessageOptions {
   optional OldOptionType required_enum_opt = 106161807;
 }
 
 // Test message using the "required_enum_opt" option defined above.
 message TestMessageWithRequiredEnumOption {
   option (required_enum_opt) = { value: OLD_VALUE };
 }