Merge "Prevent a crash when constructing NSSL." into qt-dev am: a9828ff519

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16611809

Change-Id: If26f91fd0f0e4d566ac056eb9b04513f4452bf67

packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayout.java

@@ -714,6 +714,9 @@ public class NotificationStackScrollLayout extends ViewGroup implements ScrollAd
     @VisibleForTesting
     @ShadeViewRefactor(RefactorComponent.SHADE_VIEW)
     public void updateFooter() {
+        if (mFooterView == null) {
+            return;
+        }
         boolean showDismissView = mClearAllEnabled && hasActiveClearableNotifications(ROWS_ALL);
         boolean showFooterView = (showDismissView ||
                 mEntryManager.getNotificationData().getActiveNotifications().size() != 0)