class ChromeWebRequest extends ChromeApi {
 static final JsObject _webRequest = chrome['webRequest'];

 ChromeWebRequest._();

 bool get available => _webRequest != null;

 /**
  * The maximum number of times that `handlerBehaviorChanged` can be called per
  * 10 minute sustained interval. `handlerBehaviorChanged` is an expensive
  * function call that shouldn't be called often.
  */
 int get MAX_HANDLER_BEHAVIOR_CHANGED_CALLS_PER_10_MINUTES => _webRequest['MAX_HANDLER_BEHAVIOR_CHANGED_CALLS_PER_10_MINUTES'];

 /**
  * Needs to be called when the behavior of the webRequest handlers has changed
  * to prevent incorrect handling due to caching. This function call is
  * expensive. Don't call it often.
  */
 Future handlerBehaviorChanged() {
   if (_webRequest == null) _throwNotAvailable();

   var completer = new ChromeCompleter.noArgs();
   _webRequest.callMethod('handlerBehaviorChanged', [completer.callback]);
   return completer.future;
 }

 /**
  * Fired when a request is about to occur.
  */
 Stream<Map> get onBeforeRequest => _onBeforeRequest.stream;

 final ChromeStreamController<Map> _onBeforeRequest =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onBeforeRequest', mapify);

 /**
  * Fired before sending an HTTP request, once the request headers are
  * available. This may occur after a TCP connection is made to the server, but
  * before any HTTP data is sent.
  */
 Stream<Map> get onBeforeSendHeaders => _onBeforeSendHeaders.stream;

 final ChromeStreamController<Map> _onBeforeSendHeaders =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onBeforeSendHeaders', mapify);

 /**
  * Fired just before a request is going to be sent to the server
  * (modifications of previous onBeforeSendHeaders callbacks are visible by the
  * time onSendHeaders is fired).
  */
 Stream<Map> get onSendHeaders => _onSendHeaders.stream;

 final ChromeStreamController<Map> _onSendHeaders =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onSendHeaders', mapify);

 /**
  * Fired when HTTP response headers of a request have been received.
  */
 Stream<Map> get onHeadersReceived => _onHeadersReceived.stream;

 final ChromeStreamController<Map> _onHeadersReceived =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onHeadersReceived', mapify);

 /**
  * Fired when an authentication failure is received. The listener has three
  * options: it can provide authentication credentials, it can cancel the
  * request and display the error page, or it can take no action on the
  * challenge. If bad user credentials are provided, this may be called
  * multiple times for the same request.
  */
 Stream<OnAuthRequiredEvent> get onAuthRequired => _onAuthRequired.stream;

 final ChromeStreamController<OnAuthRequiredEvent> _onAuthRequired =
     new ChromeStreamController<OnAuthRequiredEvent>.twoArgs(_webRequest, 'onAuthRequired', _createOnAuthRequiredEvent);

 /**
  * Fired when the first byte of the response body is received. For HTTP
  * requests, this means that the status line and response headers are
  * available.
  */
 Stream<Map> get onResponseStarted => _onResponseStarted.stream;

 final ChromeStreamController<Map> _onResponseStarted =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onResponseStarted', mapify);

 /**
  * Fired when a server-initiated redirect is about to occur.
  */
 Stream<Map> get onBeforeRedirect => _onBeforeRedirect.stream;

 final ChromeStreamController<Map> _onBeforeRedirect =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onBeforeRedirect', mapify);

 /**
  * Fired when a request is completed.
  */
 Stream<Map> get onCompleted => _onCompleted.stream;

 final ChromeStreamController<Map> _onCompleted =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onCompleted', mapify);

 /**
  * Fired when an error occurs.
  */
 Stream<Map> get onErrorOccurred => _onErrorOccurred.stream;

 final ChromeStreamController<Map> _onErrorOccurred =
     new ChromeStreamController<Map>.oneArg(_webRequest, 'onErrorOccurred', mapify);

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