Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/objectivec/GPBWireFormat.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 31 matching lines @@
 }
 
 GPBWireFormat GPBWireFormatGetTagWireType(uint32_t tag) {
   return (GPBWireFormat)(tag & GPBWireFormatTagTypeMask);
 }
 
 uint32_t GPBWireFormatGetTagFieldNumber(uint32_t tag) {
   return GPBLogicalRightShift32(tag, GPBWireFormatTagTypeBits);
 }
 
-BOOL GPBWireFormatIsValidTag(uint32_t tag) {
-  uint32_t formatBits = (tag & GPBWireFormatTagTypeMask);
-  // The valid GPBWireFormat* values are 0-5, anything else is not a valid tag.
-  BOOL result = (formatBits <= 5);
-  return result;
-}
-
 GPBWireFormat GPBWireFormatForType(GPBDataType type, BOOL isPacked) {
   if (isPacked) {
     return GPBWireFormatLengthDelimited;
   }
 
   static const GPBWireFormat format[GPBDataType_Count] = {
       GPBWireFormatVarint,           // GPBDataTypeBool
       GPBWireFormatFixed32,          // GPBDataTypeFixed32
       GPBWireFormatFixed32,          // GPBDataTypeSFixed32
       GPBWireFormatFixed32,          // GPBDataTypeFloat
       GPBWireFormatFixed64,          // GPBDataTypeFixed64
       GPBWireFormatFixed64,          // GPBDataTypeSFixed64
       GPBWireFormatFixed64,          // GPBDataTypeDouble
       GPBWireFormatVarint,           // GPBDataTypeInt32
       GPBWireFormatVarint,           // GPBDataTypeInt64
       GPBWireFormatVarint,           // GPBDataTypeSInt32
       GPBWireFormatVarint,           // GPBDataTypeSInt64
       GPBWireFormatVarint,           // GPBDataTypeUInt32
       GPBWireFormatVarint,           // GPBDataTypeUInt64
       GPBWireFormatLengthDelimited,  // GPBDataTypeBytes
       GPBWireFormatLengthDelimited,  // GPBDataTypeString
       GPBWireFormatLengthDelimited,  // GPBDataTypeMessage
       GPBWireFormatStartGroup,       // GPBDataTypeGroup
       GPBWireFormatVarint            // GPBDataTypeEnum
   };
   return format[type];
 }