Merge "Add NonNull annotation to getAllSubscriptionInfoList"

telephony/java/android/telephony/SubscriptionManager.java

@@ -1365,6 +1365,7 @@ public class SubscriptionManager {
      * include those that were inserted before, maybe empty but not null.
      * @hide
      */
+    @NonNull
     @UnsupportedAppUsage
     public List<SubscriptionInfo> getAllSubscriptionInfoList() {
         if (VDBG) logd("[getAllSubscriptionInfoList]+");
@@ -1382,7 +1383,7 @@ public class SubscriptionManager {
         }
 
         if (result == null) {
-            result = new ArrayList<>();
+            result = Collections.emptyList();
         }
         return result;
     }