question: @ TargetApi ( Build . VERSION_CODES . LOLLIPOP ) private static boolean relaunchTask ( int tabId ) { if ( tabId == Tab . INVALID_TAB_ID ) return false ; Context context = ApplicationStatus . getApplicationContext ( ) ; ActivityManager manager = ( ActivityManager ) context . getSystemService ( Context . ACTIVITY_SERVICE ) ; for ( AppTask task : manager . getAppTasks ( ) ) { RecentTaskInfo info = DocumentUtils . getTaskInfoFromTask ( task ) ; if ( info == null ) continue ; int id = ActivityDelegate . getTabIdFromIntent ( info . baseIntent ) ; if ( id != tabId ) continue ; DocumentTabModelSelector . setPrioritizedTabId ( id ) ; if ( ! moveToFront ( task ) ) continue ; return true ; } return false ; }
target:  Bring the task matching the given tab ID to the front.