Merge "Start tracking unknownvisibility immediately for launchBehind" into udc-dev am: 440cf52261

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23089553

Change-Id: I4fa1de0701d2d755c56ffe2a9aae2419569b505a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

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

@@ -5170,6 +5170,12 @@ class Task extends TaskFragment {
             // task.
             r.setVisibility(true);
             ensureActivitiesVisible(null, 0, !PRESERVE_WINDOWS);
+            // If launching behind, the app will start regardless of what's above it, so mark it
+            // as unknown even before prior `pause`. This also prevents a race between set-ready
+            // and activityPause. Launch-behind is basically only used for dream now.
+            if (!r.isVisibleRequested()) {
+                r.notifyUnknownVisibilityLaunchedForKeyguardTransition();
+            }
             // Go ahead to execute app transition for this activity since the app transition
             // will not be triggered through the resume channel.
             mDisplayContent.executeAppTransition();