Fix possible NPE

Test: manual - make sure dot works normally / no regression
Bug: 213027822
Change-Id: I819f73cb8c7d613796c3d3bb4b55b80b337c6126

libs/WindowManager/Shell/src/com/android/wm/shell/bubbles/BubbleFlyoutView.java

@@ -231,8 +231,9 @@ public class BubbleFlyoutView extends FrameLayout {
      * Fade animation for consecutive flyouts.
      */
     void animateUpdate(Bubble.FlyoutMessage flyoutMessage, PointF stackPos,
-            boolean hideDot, Runnable onHide) {
+            boolean hideDot, float[] dotCenter, Runnable onHide) {
         mOnHide = onHide;
+        mDotCenter = dotCenter;
         final Runnable afterFadeOut = () -> {
             updateFlyoutMessage(flyoutMessage);
             // Wait for TextViews to layout with updated height.

libs/WindowManager/Shell/src/com/android/wm/shell/bubbles/BubbleStackView.java

@@ -2494,6 +2494,7 @@ public class BubbleStackView extends FrameLayout
             if (mFlyout.getVisibility() == View.VISIBLE) {
                 mFlyout.animateUpdate(bubble.getFlyoutMessage(),
                         mStackAnimationController.getStackPosition(), !bubble.showDot(),
+                        bubble.getIconView().getDotCenter(),
                         mAfterFlyoutHidden /* onHide */);
             } else {
                 mFlyout.setVisibility(INVISIBLE);