Revert "third_party/protobuf: Update to HEAD (83d681ee2c)"

third_party/protobuf/src/google/protobuf/compiler/csharp/csharp_enum.cc

 // 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 42 matching lines @@
 EnumGenerator::EnumGenerator(const EnumDescriptor* descriptor, const Options* options) :
     SourceGeneratorBase(descriptor->file(), options),
     descriptor_(descriptor) {
 }
 
 EnumGenerator::~EnumGenerator() {
 }
 
 void EnumGenerator::Generate(io::Printer* printer) {
   WriteEnumDocComment(printer, descriptor_);
+  WriteGeneratedCodeAttributes(printer);
   printer->Print("$access_level$ enum $name$ {\n",
                  "access_level", class_access_level(),
                  "name", descriptor_->name());
   printer->Indent();
   std::set<string> used_names;
   for (int i = 0; i < descriptor_->value_count(); i++) {
       WriteEnumValueDocComment(printer, descriptor_->value(i));
       string original_name = descriptor_->value(i)->name();
-      string name = GetEnumValueName(descriptor_->name(), descriptor_->value(i)->name());
+      string name = options()->legacy_enum_values
+          ? descriptor_->value(i)->name()
+          : GetEnumValueName(descriptor_->name(), descriptor_->value(i)->name());
       // Make sure we don't get any duplicate names due to prefix removal.
       while (!used_names.insert(name).second) {
         // It's possible we'll end up giving this warning multiple times, but that's better than not at all.
         GOOGLE_LOG(WARNING) << "Duplicate enum value " << name << " (originally " << original_name
           << ") in " << descriptor_->name() << "; adding underscore to distinguish";
         name += "_";
       }
       printer->Print("[pbr::OriginalName(\"$original_name$\")] $name$ = $number$,\n",
          "original_name", original_name,
          "name", name,
          "number", SimpleItoa(descriptor_->value(i)->number()));         
   }
   printer->Outdent();
   printer->Print("}\n");
   printer->Print("\n");
 }
 
 }  // namespace csharp
 }  // namespace compiler
 }  // namespace protobuf
 }  // namespace google