update elements and fix some bugs

lib/google_signin_aware.dart

 // DO NOT EDIT: auto-generated with `pub run custom_element_apigen:update`
 
 /// Dart API for the polymer element `google_signin_aware`.
 @HtmlImport('google_signin_aware_nodart.html')
 library polymer_elements.lib.src.google_signin.google_signin_aware;
 
 import 'dart:html';
 import 'dart:js' show JsArray, JsObject;
 import 'package:web_components/web_components.dart';
 import 'package:polymer_interop/polymer_interop.dart';
 import 'google_js_api.dart';
 
 /// `google-signin-aware` is used to enable authentication in custom elements by
 /// interacting with a google-signin element that needs to be present somewhere
 /// on the page.
 ///
 /// The `scopes` attribute allows you to specify which scope permissions are required
 /// (e.g do you want to allow interaction with the Google Drive API).
 ///
 /// The `google-signin-aware-success` event is triggered when a user successfully
-/// authenticates. The `google-signin-aware-signed-out` event is triggered
-/// when a user explicitely signs out via the google-signin element.
+/// authenticates. If either `offline` or `offlineAlwaysPrompt` is set to true, successful
+/// authentication will also trigger the `google-signin-offline-success`event.
+/// The `google-signin-aware-signed-out` event is triggered when a user explicitly
+/// signs out via the google-signin element.
 ///
 /// You can bind to `isAuthorized` property to monitor authorization state.
 /// ##### Example
 ///
 ///     <google-signin-aware scopes="https://www.googleapis.com/auth/drive"></google-signin-aware>
+///
+///
+/// ##### Example with offline
+///     <template id="awareness" is="dom-bind">
+///       <google-signin-aware
+///           scopes="https://www.googleapis.com/auth/drive"
+///           offline
+///           on-google-signin-aware-success="handleSignin"
+///           on-google-signin-offline-success="handleOffline"></google-signin-aware>
+///     <\/template>
+///     <script>
+///       var aware = document.querySelector('#awareness');
+///       aware.handleSignin = function(response) {
+///         var user = gapi.auth2.getAuthInstance().currentUser.get();
+///         console.log('User name: ' + user.getBasicProfile().getName());
+///       };
+///       aware.handleOffline = function(response) {
+///         console.log('Offline code received: ' + response.detail.code);
+///         // Here you would POST response.detail.code to your webserver, which can
+///         // exchange the authorization code for an access token. More info at:
+///         // https://developers.google.com/identity/protocols/OAuth2WebServer
+///       };
+///     <\/script>
 @CustomElementProxy('google-signin-aware')
 class GoogleSigninAware extends HtmlElement with CustomElementProxyMixin, PolymerBase {
   GoogleSigninAware.created() : super.created();
   factory GoogleSigninAware() => new Element.tag('google-signin-aware');
 
   /// App package name for android over-the-air installs.
   /// See the relevant [docs](https://developers.google.com/+/web/signin/android-app-installs)
   String get appPackageName => jsElement[r'appPackageName'];
   set appPackageName(String value) { jsElement[r'appPackageName'] = value; }
 
   /// a Google Developers clientId reference
   String get clientId => jsElement[r'clientId'];
   set clientId(String value) { jsElement[r'clientId'] = value; }
 
   /// The cookie policy defines what URIs have access to the session cookie
   /// remembering the user's sign-in state.
   /// See the relevant [docs](https://developers.google.com/+/web/signin/reference#determining_a_value_for_cookie_policy) for more information.
   String get cookiePolicy => jsElement[r'cookiePolicy'];
   set cookiePolicy(String value) { jsElement[r'cookiePolicy'] = value; }
 
   /// True if *any* element has google+ scopes
   bool get hasPlusScopes => jsElement[r'hasPlusScopes'];
   set hasPlusScopes(bool value) { jsElement[r'hasPlusScopes'] = value; }
 
+  /// The Google Apps domain to which users must belong to sign in.
+  /// See the relevant [docs](https://developers.google.com/identity/sign-in/web/reference) for more information.
+  String get hostedDomain => jsElement[r'hostedDomain'];
+  set hostedDomain(String value) { jsElement[r'hostedDomain'] = value; }
+
   /// True if authorizations for *this* element have been granted
   bool get isAuthorized => jsElement[r'isAuthorized'];
   set isAuthorized(bool value) { jsElement[r'isAuthorized'] = value; }
 
   /// True if additional authorizations for *any* element are required
   bool get needAdditionalAuth => jsElement[r'needAdditionalAuth'];
   set needAdditionalAuth(bool value) { jsElement[r'needAdditionalAuth'] = value; }
 
+  /// Allows for offline `access_token` retrieval during the signin process.
+  /// See also `offlineAlwaysPrompt`. You only need to set one of the two; if both
+  /// are set, the behavior of `offlineAlwaysPrompt` will override `offline`.
+  bool get offline => jsElement[r'offline'];
+  set offline(bool value) { jsElement[r'offline'] = value; }
+
+  /// Works the same as `offline` with the addition that it will always
+  /// force a re-prompt to the user, guaranteeing that you will get a
+  /// refresh_token even if the user has already granted offline access to
+  /// this application. You only need to set one of `offline` or
+  /// `offlineAlwaysPrompt`, not both.
+  bool get offlineAlwaysPrompt => jsElement[r'offlineAlwaysPrompt'];
+  set offlineAlwaysPrompt(bool value) { jsElement[r'offlineAlwaysPrompt'] = value; }
+
   /// The app activity types you want to write on behalf of the user
   /// (e.g http://schemas.google.com/AddActivity)
   String get requestVisibleActions => jsElement[r'requestVisibleActions'];
   set requestVisibleActions(String value) { jsElement[r'requestVisibleActions'] = value; }
 
   /// The scopes to provide access to (e.g https://www.googleapis.com/auth/drive)
   /// and should be space-delimited.
   String get scopes => jsElement[r'scopes'];
   set scopes(String value) { jsElement[r'scopes'] = value; }
 
   /// True if user is signed in
   bool get signedIn => jsElement[r'signedIn'];
   set signedIn(bool value) { jsElement[r'signedIn'] = value; }
 
   /// pops up the authorization dialog
   signIn() =>
       jsElement.callMethod('signIn', []);
 
   /// signs user out
   signOut() =>
       jsElement.callMethod('signOut', []);
 }