update elements and fix some bugs

lib/google_signin_aware.dart

Index: lib/google_signin_aware.dart
diff --git a/lib/google_signin_aware.dart b/lib/google_signin_aware.dart
index 6777058230c58dc4f3405fa8623c671725e2bb03..c35d7d5c59f7d866edb9213676c16de549c37e68 100644
--- a/lib/google_signin_aware.dart
+++ b/lib/google_signin_aware.dart
@@ -18,13 +18,38 @@ import 'google_js_api.dart';
 /// (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();
@@ -49,6 +74,11 @@ class GoogleSigninAware extends HtmlElement with CustomElementProxyMixin, Polyme
   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; }
@@ -57,6 +87,20 @@ class GoogleSigninAware extends HtmlElement with CustomElementProxyMixin, Polyme
   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'];