class ChromePageAction extends ChromeApi {
 static final JsObject _pageAction = chrome['pageAction'];

 ChromePageAction._();

 bool get available => _pageAction != null;

 /**
  * Shows the page action. The page action is shown whenever the tab is
  * selected.
  * 
  * [tabId] The id of the tab for which you want to modify the page action.
  */
 void show(int tabId) {
   if (_pageAction == null) _throwNotAvailable();

   _pageAction.callMethod('show', [tabId]);
 }

 /**
  * Hides the page action.
  * 
  * [tabId] The id of the tab for which you want to modify the page action.
  */
 void hide(int tabId) {
   if (_pageAction == null) _throwNotAvailable();

   _pageAction.callMethod('hide', [tabId]);
 }

 /**
  * Sets the title of the page action. This is displayed in a tooltip over the
  * page action.
  */
 void setTitle(PageActionSetTitleParams details) {
   if (_pageAction == null) _throwNotAvailable();

   _pageAction.callMethod('setTitle', [jsify(details)]);
 }

 /**
  * Gets the title of the page action.
  */
 Future<String> getTitle(PageActionGetTitleParams details) {
   if (_pageAction == null) _throwNotAvailable();

   var completer = new ChromeCompleter<String>.oneArg();
   _pageAction.callMethod('getTitle', [jsify(details), completer.callback]);
   return completer.future;
 }

 /**
  * Sets the icon for the page action. The icon can be specified either as the
  * path to an image file or as the pixel data from a canvas element, or as
  * dictionary of either one of those. Either the <b>path</b> or the
  * <b>imageData</b> property must be specified.
  */
 Future setIcon(PageActionSetIconParams details) {
   if (_pageAction == null) _throwNotAvailable();

   var completer = new ChromeCompleter.noArgs();
   _pageAction.callMethod('setIcon', [jsify(details), completer.callback]);
   return completer.future;
 }

 /**
  * Sets the html document to be opened as a popup when the user clicks on the
  * page action's icon.
  */
 void setPopup(PageActionSetPopupParams details) {
   if (_pageAction == null) _throwNotAvailable();

   _pageAction.callMethod('setPopup', [jsify(details)]);
 }

 /**
  * Gets the html document set as the popup for this page action.
  */
 Future<String> getPopup(PageActionGetPopupParams details) {
   if (_pageAction == null) _throwNotAvailable();

   var completer = new ChromeCompleter<String>.oneArg();
   _pageAction.callMethod('getPopup', [jsify(details), completer.callback]);
   return completer.future;
 }

 /**
  * Fired when a page action icon is clicked.  This event will not fire if the
  * page action has a popup.
  */
 Stream<Tab> get onClicked => _onClicked.stream;

 final ChromeStreamController<Tab> _onClicked =
     new ChromeStreamController<Tab>.oneArg(_pageAction, 'onClicked', _createTab);

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