Inline no-op IndicesModule#getEngineFactories

This method was introduced in elastic#31183 but it has no effect and is never
overridden so this commit removes it.

server/src/main/java/org/elasticsearch/indices/IndicesModule.java

@@ -28,12 +28,9 @@
 import org.elasticsearch.common.inject.AbstractModule;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
-import org.elasticsearch.index.IndexSettings;
-import org.elasticsearch.index.engine.EngineFactory;
 import org.elasticsearch.index.mapper.BinaryFieldMapper;
 import org.elasticsearch.index.mapper.BooleanFieldMapper;
 import org.elasticsearch.index.mapper.CompletionFieldMapper;
-import org.elasticsearch.index.mapper.TimestampFieldMapper;
 import org.elasticsearch.index.mapper.DateFieldMapper;
 import org.elasticsearch.index.mapper.FieldAliasMapper;
 import org.elasticsearch.index.mapper.FieldNamesFieldMapper;
@@ -54,6 +51,7 @@
 import org.elasticsearch.index.mapper.SeqNoFieldMapper;
 import org.elasticsearch.index.mapper.SourceFieldMapper;
 import org.elasticsearch.index.mapper.TextFieldMapper;
+import org.elasticsearch.index.mapper.TimestampFieldMapper;
 import org.elasticsearch.index.mapper.TypeFieldMapper;
 import org.elasticsearch.index.mapper.VersionFieldMapper;
 import org.elasticsearch.index.seqno.RetentionLeaseBackgroundSyncAction;
@@ -66,12 +64,10 @@
 import org.elasticsearch.plugins.MapperPlugin;
 
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Optional;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -254,8 +250,4 @@ public MapperRegistry getMapperRegistry() {
         return mapperRegistry;
     }
 
-    public Collection<Function<IndexSettings, Optional<EngineFactory>>> getEngineFactories() {
-        return Collections.emptyList();
-    }
-
 }

server/src/main/java/org/elasticsearch/node/Node.java

@@ -440,10 +440,8 @@ protected Node(final Environment initialEnvironment,
             // collect engine factory providers from server and from plugins
             final Collection<EnginePlugin> enginePlugins = pluginsService.filterPlugins(EnginePlugin.class);
             final Collection<Function<IndexSettings, Optional<EngineFactory>>> engineFactoryProviders =
-                    Stream.concat(
-                            indicesModule.getEngineFactories().stream(),
-                            enginePlugins.stream().map(plugin -> plugin::getEngineFactory))
-                    .collect(Collectors.toList());
+                    enginePlugins.stream().map(plugin -> (Function<IndexSettings, Optional<EngineFactory>>)plugin::getEngineFactory)
+                            .collect(Collectors.toList());
 
 
             final Map<String, IndexStorePlugin.DirectoryFactory> indexStoreFactories =