Fix NPE

            // We may need to schedule some toast windows to be removed. The

            // toasts for an app that does not have input focus are removed

            // within a timeout to prevent apps to redress other apps' UI.

            oldFocus.getDisplayContent().scheduleToastWindowsTimeoutIfNeededLocked(

            getDefaultDisplayContentLocked().scheduleToastWindowsTimeoutIfNeededLocked(

                        oldFocus, newFocus);

            Trace.traceEnd(Trace.TRACE_TAG_WINDOW_MANAGER);