class ChromeTabCapture extends ChromeApi {
 static final JsObject _tabCapture = chrome['tabCapture'];

 ChromeTabCapture._();

 bool get available => _tabCapture != null;

 /**
  * Captures the visible area of the currently active tab. This method can only
  * be used on the currently active page after the extension has been
  * _invoked_, similar to the way that <a href="activeTab.html">activeTab</a>
  * works.
  * [options]: Configures the returned media stream.
  * [callback]: Callback with either the stream returned or null.
  */
 Future<LocalMediaStream> capture(CaptureOptions options) {
   if (_tabCapture == null) _throwNotAvailable();

   var completer = new ChromeCompleter<LocalMediaStream>.oneArg(_createLocalMediaStream);
   _tabCapture.callMethod('capture', [jsify(options), completer.callback]);
   return completer.future;
 }

 /**
  * Returns a list of tabs that have requested capture or are being captured,
  * i.e. status != stopped and status != error. This allows extensions to
  * inform the user that there is an existing tab capture that would prevent a
  * new tab capture from succeeding (or to prevent redundant requests for the
  * same tab).
  */
 Future<List<CaptureInfo>> getCapturedTabs() {
   if (_tabCapture == null) _throwNotAvailable();

   var completer = new ChromeCompleter<List<CaptureInfo>>.oneArg((e) => listify(e, _createCaptureInfo));
   _tabCapture.callMethod('getCapturedTabs', [completer.callback]);
   return completer.future;
 }

 Stream<CaptureInfo> get onStatusChanged => _onStatusChanged.stream;

 final ChromeStreamController<CaptureInfo> _onStatusChanged =
     new ChromeStreamController<CaptureInfo>.oneArg(_tabCapture, 'onStatusChanged', _createCaptureInfo);

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