Merge "Fix bubble shows empty content after rotating the device." into rvc-dev am: e8a51880b5

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12070365

Change-Id: I602592d3cc928b745d93068732410fa57067f31a

services/core/java/com/android/server/wm/ActivityStack.java

@@ -2058,7 +2058,12 @@ class ActivityStack extends Task {
                     if (r.mLaunchTaskBehind) {
                         transit = TRANSIT_TASK_OPEN_BEHIND;
                     } else if (getDisplay().isSingleTaskInstance()) {
+                        // If a new task is being launched in a single task display, we don't need
+                        // to play normal animation, but need to trigger a callback when an app
+                        // transition is actually handled. So ignore already prepared activity, and
+                        // override it.
                         transit = TRANSIT_SHOW_SINGLE_TASK_DISPLAY;
+                        keepCurTransition = false;
                     } else {
                         // If a new task is being launched, then mark the existing top activity as
                         // supporting picture-in-picture while pausing only if the starting activity