Prevent public access by making multi-db methods package-private

Author: tom-andersen

firebase-firestore/src/main/java/com/google/firebase/firestore/FirebaseFirestore.java

@@ -152,7 +152,7 @@ public static FirebaseFirestore getInstance(@NonNull FirebaseApp app) {
    * @returns The {@link FirebaseFirestore} instance of the provided app.
    */
   @NonNull
-  public static FirebaseFirestore getInstance(@NonNull String database) {
+  static FirebaseFirestore getInstance(@NonNull String database) {
     return getInstance(getDefaultFirebaseApp(), database);
   }
 
@@ -166,7 +166,7 @@ public static FirebaseFirestore getInstance(@NonNull String database) {
    * @returns The {@link FirebaseFirestore} instance of the provided app.
    */
   @NonNull
-  public static FirebaseFirestore getInstance(@NonNull FirebaseApp app, @NonNull String database) {
+  static FirebaseFirestore getInstance(@NonNull FirebaseApp app, @NonNull String database) {
     checkNotNull(app, "Provided FirebaseApp must not be null.");
     checkNotNull(database, "Provided database name must not be null.");
     FirestoreMultiDbComponent component = app.get(FirestoreMultiDbComponent.class);