ICU 56 step 4: Apply post-56 fixes for measure/date format

source/i18n/unicode/measfmt.h

Index: source/i18n/unicode/measfmt.h
diff --git a/source/i18n/unicode/measfmt.h b/source/i18n/unicode/measfmt.h
index 61a1e86d9c431e7c18a48ccb976e37c16ed82c1b..ee054274194243f5a958afebbdc913cb003cdc87 100644
--- a/source/i18n/unicode/measfmt.h
+++ b/source/i18n/unicode/measfmt.h
@@ -327,17 +327,19 @@ class U_I18N_API MeasureFormat : public Format {
     // shared across instances.
     ListFormatter *listFormatter;
 
-    const QuantityFormatter *getQuantityFormatter(
-            int32_t index,
-            int32_t widthIndex,
-            UErrorCode &status) const;
+    const SimplePatternFormatter *getFormatterOrNull(
+            const MeasureUnit &unit, UMeasureFormatWidth width, int32_t index) const;
+
+    const SimplePatternFormatter *getFormatter(
+            const MeasureUnit &unit, UMeasureFormatWidth width, int32_t index,
+            UErrorCode &errorCode) const;
 
-    const SimplePatternFormatter *getPerUnitFormatter(
-            int32_t index,
-            int32_t widthIndex) const;
+    const SimplePatternFormatter *getPluralFormatter(
+            const MeasureUnit &unit, UMeasureFormatWidth width, int32_t index,
+            UErrorCode &errorCode) const;
 
     const SimplePatternFormatter *getPerFormatter(
-            int32_t widthIndex,
+            UMeasureFormatWidth width,
             UErrorCode &status) const;
 
     int32_t withPerUnitAndAppend(