class ChromeSessions extends ChromeApi {
 static final JsObject _sessions = chrome['sessions'];

 ChromeSessions._();

 bool get available => _sessions != null;

 /**
  * The maximum number of [Session] that will be included in a requested list.
  */
 int get MAX_SESSION_RESULTS => _sessions['MAX_SESSION_RESULTS'];

 /**
  * Gets the list of recently closed tabs and/or windows.
  * 
  * Returns:
  * The list of closed entries in reverse order that they were closed (the most
  * recently closed tab or window will be at index `0`).The entries may contain
  * either tabs or windows.
  */
 Future<List<Session>> getRecentlyClosed([Filter filter]) {
   if (_sessions == null) _throwNotAvailable();

   var completer = new ChromeCompleter<List<Session>>.oneArg((e) => listify(e, _createSession));
   _sessions.callMethod('getRecentlyClosed', [jsify(filter), completer.callback]);
   return completer.future;
 }

 /**
  * Retrieves all devices with synced sessions.
  * 
  * Returns:
  * The list of [Device] objects for each synced session, sorted in order from
  * device with most recently modified session to device with least recently
  * modified session. [tabs.Tab] objects are sorted by recency in the
  * [windows.Window] of the [Session] objects.
  */
 Future<List<Device>> getDevices([Filter filter]) {
   if (_sessions == null) _throwNotAvailable();

   var completer = new ChromeCompleter<List<Device>>.oneArg((e) => listify(e, _createDevice));
   _sessions.callMethod('getDevices', [jsify(filter), completer.callback]);
   return completer.future;
 }

 /**
  * Reopens a [windows.Window] or [tabs.Tab], with an optional callback to run
  * when the entry has been restored.
  * 
  * [sessionId] The [windows.Window.sessionId], or [tabs.Tab.sessionId] to
  * restore.
  * 
  * Returns:
  * A [Session] containing the restored [windows.Window] or [tabs.Tab] object.
  */
 Future<Session> restore([String sessionId]) {
   if (_sessions == null) _throwNotAvailable();

   var completer = new ChromeCompleter<Session>.oneArg(_createSession);
   _sessions.callMethod('restore', [sessionId, completer.callback]);
   return completer.future;
 }

 void _throwNotAvailable() {
   throw new UnsupportedError("'chrome.sessions' is not available");
 }
}