Merge "Start tracking unknownvisibility immediately for launchBehind" into udc-dev

            // 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();