Merge "Make sure topActivity always retrieves focus when move task to back" into udc-dev

            // Usually resuming a top activity triggers the next app transition, but nothing's got

            // resumed in this case, so we need to execute it explicitly.

            mDisplayContent.executeAppTransition();

            mDisplayContent.setFocusedApp(topActivity);

        } else {

            mRootWindowContainer.resumeFocusedTasksTopActivities();

        }