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

third_party/protobuf/ruby/ext/google/protobuf_c/protobuf.h

Index: third_party/protobuf/ruby/ext/google/protobuf_c/protobuf.h
diff --git a/third_party/protobuf/ruby/ext/google/protobuf_c/protobuf.h b/third_party/protobuf/ruby/ext/google/protobuf_c/protobuf.h
index d5ced5672dece18453ffb912d2251c33beb9778e..2834c8944a6335b10964b23924f412bc19a19671 100644
--- a/third_party/protobuf/ruby/ext/google/protobuf_c/protobuf.h
+++ b/third_party/protobuf/ruby/ext/google/protobuf_c/protobuf.h
@@ -166,8 +166,6 @@ extern VALUE cBuilder;
 extern VALUE cError;
 extern VALUE cParseError;
 
-extern VALUE map_parse_frames;
-
 // We forward-declare all of the Ruby method implementations here because we
 // sometimes call the methods directly across .c files, rather than going
 // through Ruby's method dispatching (e.g. during message parse). It's cleaner
@@ -315,7 +313,7 @@ void native_slot_dup(upb_fieldtype_t type, void* to, void* from);
 void native_slot_deep_copy(upb_fieldtype_t type, void* to, void* from);
 bool native_slot_eq(upb_fieldtype_t type, void* mem1, void* mem2);
 
-VALUE native_slot_encode_and_freeze_string(upb_fieldtype_t type, VALUE value);
+void native_slot_validate_string_encoding(upb_fieldtype_t type, VALUE value);
 void native_slot_check_int_range_precision(upb_fieldtype_t type, VALUE value);
 
 extern rb_encoding* kRubyStringUtf8Encoding;
@@ -368,7 +366,6 @@ RepeatedField* ruby_to_RepeatedField(VALUE value);
 VALUE RepeatedField_each(VALUE _self);
 VALUE RepeatedField_index(int argc, VALUE* argv, VALUE _self);
 void* RepeatedField_index_native(VALUE _self, int index);
-int RepeatedField_size(VALUE _self);
 VALUE RepeatedField_index_set(VALUE _self, VALUE _index, VALUE val);
 void RepeatedField_reserve(RepeatedField* self, int new_size);
 VALUE RepeatedField_push(VALUE _self, VALUE val);