ICU-20568 Cleanup: drop declaration for no longer existing factory.
diff --git a/icu4c/source/i18n/number_longnames.h b/icu4c/source/i18n/number_longnames.h
index ace517c..4146f76 100644
--- a/icu4c/source/i18n/number_longnames.h
+++ b/icu4c/source/i18n/number_longnames.h
@@ -188,12 +188,6 @@
// the private constructors.
friend class MemoryPool<MixedUnitLongNameHandler>;
- // Fills in LongNameHandler fields for formatting mixed units. Each unit in
- // a mixed unit must be a built-in unit.
- static void forMixedUnit(const Locale &loc, const MeasureUnit &unit, const UNumberUnitWidth &width,
- const PluralRules *rules, const MicroPropsGenerator *parent,
- MixedUnitLongNameHandler *fillIn, UErrorCode &status);
-
// For a mixed unit, returns a Modifier that takes only one parameter: the
// smallest and final unit of the set. The bigger units' values and labels
// get baked into this Modifier, together with the unit label of the final