Handle task visibility change to show the surface

- When a new task organizer is registered, while a task is invisible,
  onTaskAppeared() may get called with isVisible=false.
- Later on when visibility becomes true, onTaskAppeared() is not called
  and hence that surface would still remain hidden.
- Handle this scenario in onTaskInfoChanged to make sure surface is
  shown correctly.

Fix: 272296051
Test: Tested manually by triggering this case on gcar_ui_portrait
Change-Id: Ie61be170ae92dac1c4eab102e76629f989afa64c

libs/WindowManager/Shell/src/com/android/wm/shell/fullscreen/FullscreenTaskListener.java

@@ -129,6 +129,7 @@ public class FullscreenTaskListener implements ShellTaskOrganizer.TaskListener {
     public void onTaskInfoChanged(RunningTaskInfo taskInfo) {
         final State state = mTasks.get(taskInfo.taskId);
         final Point oldPositionInParent = state.mTaskInfo.positionInParent;
+        boolean oldVisible = state.mTaskInfo.isVisible;
 
         if (mWindowDecorViewModelOptional.isPresent()) {
             mWindowDecorViewModelOptional.get().onTaskInfoChanged(taskInfo);
@@ -138,12 +139,18 @@ public class FullscreenTaskListener implements ShellTaskOrganizer.TaskListener {
         updateRecentsForVisibleFullscreenTask(taskInfo);
 
         final Point positionInParent = state.mTaskInfo.positionInParent;
-        if (!oldPositionInParent.equals(state.mTaskInfo.positionInParent)) {
+        boolean positionInParentChanged = !oldPositionInParent.equals(positionInParent);
+        boolean becameVisible = !oldVisible && state.mTaskInfo.isVisible;
+
+        if (becameVisible || positionInParentChanged) {
             mSyncQueue.runInSync(t -> {
                 if (!state.mLeash.isValid()) {
                     // Task vanished before sync completion
                     return;
                 }
+                if (becameVisible) {
+                    t.show(state.mLeash);
+                }
                 t.setPosition(state.mLeash, positionInParent.x, positionInParent.y);
             });
         }