Review feedback

Author: wilhuff

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

@@ -901,6 +901,7 @@ private ListenerRegistration addSnapshotListenerInternal(
       @Nullable Activity activity,
       EventListener<QuerySnapshot> userListener) {
 
+    // Convert from ViewSnapshots to QuerySnapshots.
     EventListener<ViewSnapshot> viewListener =
         (@Nullable ViewSnapshot snapshot, @Nullable FirebaseFirestoreException error) -> {
           if (error != null) {
@@ -914,6 +915,7 @@ private ListenerRegistration addSnapshotListenerInternal(
           userListener.onEvent(querySnapshot, null);
         };
 
+    // Call the viewListener on the userExecutor.
     AsyncEventListener<ViewSnapshot> asyncListener =
         new AsyncEventListener<>(executor, viewListener);
 

firebase-firestore/src/main/java/com/google/firebase/firestore/core/ListenerRegistrationImpl.java

@@ -27,7 +27,6 @@ public class ListenerRegistrationImpl implements ListenerRegistration {
   /** The event listener for the query that raises events asynchronously. */
   private final AsyncEventListener<ViewSnapshot> asyncEventListener;
 
-  /** Creates a new ListenerRegistration. Is activity-scoped if and only if activity is non-null. */
   public ListenerRegistrationImpl(
       FirestoreClient client,
       QueryListener queryListener,