class ChromeExtension extends ChromeApi {
 static final JsObject _extension = chrome['extension'];

 ChromeExtension._();

 bool get available => _extension != null;

 /**
  * Set for the lifetime of a callback if an ansychronous extension api has
  * resulted in an error. If no error has occured lastError will be
  * [undefined].
  */
 LastErrorExtension get lastError => _createLastErrorExtension(_extension['lastError']);

 /**
  * True for content scripts running inside incognito tabs, and for extension
  * pages running inside an incognito process. The latter only applies to
  * extensions with 'split' incognito_behavior.
  */
 bool get inIncognitoContext => _extension['inIncognitoContext'];

 /**
  * Deprecated: Please use sendMessage.
  * 
  * [extensionId] The extension ID of the extension you want to connect to. If
  * omitted, default is your own extension.
  * 
  * Returns:
  * The JSON response object sent by the handler of the request. If an error
  * occurs while connecting to the extension, the callback will be called with
  * no arguments and [runtime.lastError] will be set to the error message.
  */
 Future<dynamic> sendRequest(dynamic request, [String extensionId]) {
   if (_extension == null) _throwNotAvailable();

   var completer = new ChromeCompleter<dynamic>.oneArg();
   _extension.callMethod('sendRequest', [extensionId, jsify(request), completer.callback]);
   return completer.future;
 }

 /**
  * Converts a relative path within an extension install directory to a
  * fully-qualified URL.
  * 
  * [path] A path to a resource within an extension expressed relative to its
  * install directory.
  * 
  * Returns:
  * The fully-qualified URL to the resource.
  */
 String getURL(String path) {
   if (_extension == null) _throwNotAvailable();

   return _extension.callMethod('getURL', [path]);
 }

 /**
  * Returns an array of the JavaScript 'window' objects for each of the pages
  * running inside the current extension.
  * 
  * Returns:
  * Array of global objects
  */
 List<Window> getViews([ExtensionGetViewsParams fetchProperties]) {
   if (_extension == null) _throwNotAvailable();

   var ret = _extension.callMethod('getViews', [jsify(fetchProperties)]);
   return ret;
 }

 /**
  * Returns the JavaScript 'window' object for the background page running
  * inside the current extension. Returns null if the extension has no
  * background page.
  */
 Window getBackgroundPage() {
   if (_extension == null) _throwNotAvailable();

   return _createWindow(_extension.callMethod('getBackgroundPage'));
 }

 /**
  * Deprecated. Please use getViews({type: 'TAB'}). Returns an array of the
  * JavaScript 'window' objects for each of the tabs running inside the current
  * extension. If windowId is specified, returns only the 'window' objects of
  * tabs attached to the specified window.
  * 
  * Returns:
  * Array of global window objects
  */
 List<Window> getExtensionTabs([int windowId]) {
   if (_extension == null) _throwNotAvailable();

   var ret = _extension.callMethod('getExtensionTabs', [windowId]);
   return ret;
 }

 /**
  * Retrieves the state of the extension's access to Incognito-mode (as
  * determined by the user-controlled 'Allowed in Incognito' checkbox.
  * 
  * Returns:
  * True if the extension has access to Incognito mode, false otherwise.
  */
 Future<bool> isAllowedIncognitoAccess() {
   if (_extension == null) _throwNotAvailable();

   var completer = new ChromeCompleter<bool>.oneArg();
   _extension.callMethod('isAllowedIncognitoAccess', [completer.callback]);
   return completer.future;
 }

 /**
  * Retrieves the state of the extension's access to the 'file://' scheme (as
  * determined by the user-controlled 'Allow access to File URLs' checkbox.
  * 
  * Returns:
  * True if the extension can access the 'file://' scheme, false otherwise.
  */
 Future<bool> isAllowedFileSchemeAccess() {
   if (_extension == null) _throwNotAvailable();

   var completer = new ChromeCompleter<bool>.oneArg();
   _extension.callMethod('isAllowedFileSchemeAccess', [completer.callback]);
   return completer.future;
 }

 /**
  * Sets the value of the ap CGI parameter used in the extension's update URL.
  * This value is ignored for extensions that are hosted in the Chrome
  * Extension Gallery.
  */
 void setUpdateUrlData(String data) {
   if (_extension == null) _throwNotAvailable();

   _extension.callMethod('setUpdateUrlData', [data]);
 }

 /**
  * Deprecated: please use onMessage.
  */
 Stream<OnRequestEvent> get onRequest => _onRequest.stream;

 final ChromeStreamController<OnRequestEvent> _onRequest =
     new ChromeStreamController<OnRequestEvent>.threeArgs(_extension, 'onRequest', _createOnRequestEvent);

 /**
  * Deprecated: please use onMessageExternal.
  */
 Stream<OnRequestExternalEvent> get onRequestExternal => _onRequestExternal.stream;

 final ChromeStreamController<OnRequestExternalEvent> _onRequestExternal =
     new ChromeStreamController<OnRequestExternalEvent>.threeArgs(_extension, 'onRequestExternal', _createOnRequestExternalEvent);

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