[Engine] change loadHistoryUUID to protected, and Origin#isFromTranslog() to public (#19752)

Signed-off-by: jinnyw <jinnyw@uber.com>
Co-authored-by: jinnyw <jinnyw@uber.com>

Author: Jinny-Wang

CHANGELOG.md

@@ -33,6 +33,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Refactor the IndexingStats.Stats class to use the Builder pattern instead of constructors ([#19306](https://github.com/opensearch-project/OpenSearch/pull/19306))
 - Remove FeatureFlag.MERGED_SEGMENT_WARMER_EXPERIMENTAL_FLAG. ([#19715](https://github.com/opensearch-project/OpenSearch/pull/19715))
 -
+- Make Engine#loadHistoryUUID() protected and Origin#isFromTranslog() public ([#19753](https://github.com/opensearch-project/OpenSearch/pull/19752))
+
 ### Fixed
 - Fix Allocation and Rebalance Constraints of WeightFunction are incorrectly reset ([#19012](https://github.com/opensearch-project/OpenSearch/pull/19012))
 - Fix flaky test FieldDataLoadingIT.testIndicesFieldDataCacheSizeSetting ([#19571](https://github.com/opensearch-project/OpenSearch/pull/19571))

server/src/main/java/org/opensearch/index/engine/Engine.java

@@ -227,7 +227,7 @@ public MergedSegmentTransferTracker getMergedSegmentTransferTracker() {
     /**
      * Reads the current stored history ID from commit data.
      */
-    String loadHistoryUUID(Map<String, String> commitData) {
+    protected String loadHistoryUUID(Map<String, String> commitData) {
         final String uuid = commitData.get(HISTORY_UUID_KEY);
         if (uuid == null) {
             throw new IllegalStateException("commit doesn't contain history uuid");
@@ -1559,7 +1559,7 @@ public boolean isRecovery() {
                 return this == PEER_RECOVERY || this == LOCAL_TRANSLOG_RECOVERY;
             }
 
-            boolean isFromTranslog() {
+            public boolean isFromTranslog() {
                 return this == LOCAL_TRANSLOG_RECOVERY || this == LOCAL_RESET;
             }
         }