Fix Lint

Author: schmidt-sebastian

firebase-firestore/src/main/java/com/google/firebase/firestore/local/IndexBackfiller.java

@@ -44,15 +44,13 @@ public class IndexBackfiller {
 
   private final Scheduler scheduler;
   private final Persistence persistence;
-  private final RemoteDocumentCache remoteDocumentCache;
   private LocalDocumentsView localDocumentsView;
   private IndexManager indexManager;
   private int maxDocumentsToProcess = MAX_DOCUMENTS_TO_PROCESS;
 
   public IndexBackfiller(Persistence persistence, AsyncQueue asyncQueue) {
     this.persistence = persistence;
     this.scheduler = new Scheduler(asyncQueue);
-    this.remoteDocumentCache = persistence.getRemoteDocumentCache();
   }
 
   public void setLocalDocumentsView(LocalDocumentsView localDocumentsView) {