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

third_party/protobuf/objectivec/Tests/GPBUnknownFieldSetTest.m

 // 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 @@
 
 @implementation UnknownFieldSetTest
 
 - (void)setUp {
   allFields_ = [self allSetRepeatedCount:kGPBDefaultRepeatCount];
   allFieldsData_ = [allFields_ data];
   emptyMessage_ = [TestEmptyMessage parseFromData:allFieldsData_ error:NULL];
   unknownFields_ = emptyMessage_.unknownFields;
 }
 
+- (GPBUnknownField *)getField:(int32_t)number {
+  return [unknownFields_ getField:number];
+}
+
 // Constructs a protocol buffer which contains fields with all the same
 // numbers as allFieldsData except that each field is some other wire
 // type.
 - (NSData*)getBizarroData {
   GPBUnknownFieldSet* bizarroFields =
       [[[GPBUnknownFieldSet alloc] init] autorelease];
   NSUInteger count = [unknownFields_ countOfFields];
   int32_t tags[count];
   [unknownFields_ getTags:tags];
   for (NSUInteger i = 0; i < count; ++i) {
@@ skipping 173 matching lines @@
   [field1 addFixed32:2];
   [field1 addFixed64:3];
   [field1 addLengthDelimited:[NSData dataWithBytes:"hello" length:5]];
   [field1 addGroup:[[unknownFields_ copy] autorelease]];
   GPBUnknownField* field2 = [[[GPBUnknownField alloc] initWithNumber:2] autorelease];
   [field2 mergeFromField:field1];
   XCTAssertEqualObjects(field1, field2);
 }
 
 @end