Cleaning up some unused notifications functionality

Bug: 321154530
Test: Presubmit
Flag: N/A
Change-Id: I1ff2a4f19595659d89e7d72ee1b29036bbd54d8f

src/com/android/launcher3/notification/NotificationKeyData.java

@@ -26,13 +26,10 @@ import androidx.annotation.Nullable;
 import com.android.launcher3.Utilities;
 
 import java.util.ArrayList;
-import java.util.List;
 
 /**
  * The key data associated with the notification, used to determine what to include
  * in dots and stub popup views before they are populated.
- *
- * @see NotificationInfo for the full data used when populating the stub views.
  */
 public class NotificationKeyData {
     public final String notificationKey;
@@ -56,15 +53,6 @@ public class NotificationKeyData {
                         Notification.EXTRA_PEOPLE_LIST)));
     }
 
-    public static List<String> extractKeysOnly(
-            @NonNull List<NotificationKeyData> notificationKeys) {
-        List<String> keysOnly = new ArrayList<>(notificationKeys.size());
-        for (NotificationKeyData notificationKeyData : notificationKeys) {
-            keysOnly.add(notificationKeyData.notificationKey);
-        }
-        return keysOnly;
-    }
-
     private static String[] extractPersonKeyOnly(@Nullable ArrayList<Person> people) {
         if (people == null || people.isEmpty()) {
             return Utilities.EMPTY_STRING_ARRAY;