Fixed a crash with the headsUpManager

Since the headsUpManager is calling out in various places to
its listeners, the callbacks may query the headsupmanager
in an internally inconsistent state, such that the pinned mode is
true but there is no topEntry. Let's add a null-check for
safety here.

Bug: 137804505
Test: atest SystemUITests
Change-Id: Ibae76b555ca51ccf676228b034a614d59a8b4e8e

packages/SystemUI/src/com/android/systemui/statusbar/phone/HeadsUpManagerPhone.java

@@ -301,12 +301,15 @@ public class HeadsUpManagerPhone extends HeadsUpManager implements Dumpable,
     }
 
     public Region calculateTouchableRegion() {
-        if (!hasPinnedHeadsUp()) {
+        NotificationEntry topEntry = getTopEntry();
+        // This call could be made in an inconsistent state while the pinnedMode hasn't been
+        // updated yet, but callbacks leading out of the headsUp manager, querying it. Let's
+        // therefore also check if the topEntry is null.
+        if (!hasPinnedHeadsUp() || topEntry == null) {
             mTouchableRegion.set(0, 0, mStatusBarWindowView.getWidth(), mStatusBarHeight);
             updateRegionForNotch(mTouchableRegion);
 
         } else {
-            NotificationEntry topEntry = getTopEntry();
             if (topEntry.isChildInGroup()) {
                 final NotificationEntry groupSummary =
                         mGroupManager.getGroupSummary(topEntry.notification);