update elements and fix some bugs

lib/src/google-signin/google-signin.html

 <link rel="import" href="../polymer/polymer.html">
 <link rel="import" href="google-signin-aware.html">
 <link rel="import" href="../iron-icon/iron-icon.html">
 <link rel="import" href="../iron-icons/iron-icons.html">
 <link rel="import" href="../font-roboto/roboto.html">
 <link rel="import" href="../google-apis/google-js-api.html">
 <link rel="import" href="../paper-ripple/paper-ripple.html">
 <link rel="import" href="../paper-material/paper-material.html">
 <link rel="import" href="../iron-flex-layout/classes/iron-flex-layout.html">
 <link rel="import" href="google-icons.html">
 
 <dom-module id="google-signin">
   <link rel="import" type="css" href="google-signin.css">
   <template>
     <google-signin-aware id="aware"
       app-package-name="{{appPackageName}}"
       client-id="{{clientId}}"
       cookie-policy="{{cookiePolicy}}"
       request-visible-actions="{{requestVisibleActions}}"
+      hosted-domain="{{hostedDomain}}"
+      offline="{{offline}}"
+      offline-always-prompt="{{offlineAlwaysPrompt}}"
       scopes="{{scopes}}"
       signed-in="{{signedIn}}"
       is-authorized="{{isAuthorized}}"
       need-additional-auth="{{needAdditionalAuth}}"
       has-plus-scopes="{{hasPlusScopes}}"></google-signin-aware>
     <template is="dom-if" if="{{raised}}">
       <paper-material id="shadow" class="fit" elevation="2" animated></paper-material>
     </template>
     <div id="button"
       class$="[[_computeButtonClass(height, width, theme, signedIn, _brand, needAdditionalAuth)]]">
@@ skipping 107 matching lines @@
 
 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). Many APIs also
 need to be enabled in the Google Developers Console before you can use them.
 
 The `requestVisibleActions` attribute is necessary if you want to write app
 activities (https://developers.google.com/+/web/app-activities/) on behalf of
 the user. Please note that this attribute is only valid in combination with the
 plus.login scope (https://www.googleapis.com/auth/plus.login).
 
+The `offline` attribute allows you to get an auth code which your server can
+redeem for an offline access token
+(https://developers.google.com/identity/sign-in/web/server-side-flow).
+You can also set `offline-always-prompt` instead of `offline` to ensure that your app
+will re-prompt the user for offline access and generate a working `refresh_token`
+even if they have already granted offline access to your app in the past.
+
 Use label properties to customize prompts.
 
 The button can be styled in using the `height`, `width`, and `theme` attributes.
 These attributes help you follow the Google+ Sign-In button branding guidelines
 (https://developers.google.com/+/branding-guidelines).
 
 The `google-signin-success` event is triggered when a user successfully authenticates
-and `google-signed-out` is triggered when user signeds out.
+and `google-signed-out` is triggered when user signs out.
 You can also use `isAuthorized` attribute to observe user's authentication state.
 
 Additional events, such as `google-signout-attempted` are
 triggered when the user attempts to sign-out and successfully signs out.
 
+When requesting offline access, the `google-signin-offline-success` event is
+triggered when the user successfully consents with offline support.
+
 The `google-signin-necessary` event is fired when scopes requested via
 google-signin-aware elements require additional user permissions.
 
 #### Testing
 
 By default, the demo accompanying this element is setup to work on localhost with
 port 8080. That said, you *should* update the `clientId` to your own one for
 any apps you're building. See the Google Developers Console
 (https://console.developers.google.com) for more info.
 
@@ skipping 20 matching lines @@
      * @event google-signin-necessary
      */
 
     /**
      * Fired when signed in, and scope has been authorized
      * @param {Object} result Authorization result.
      * @event google-signin-aware-success
      */
 
     /**
+     * Fired when an offline authorization is successful.
+     * @event google-signin-offline-success
+     * @param {Object} detail
+     * @param {string} detail.code The one-time authorization code from Google.
+     *     Your application can exchange this for an `access_token` and `refresh_token`
+     */
+
+    /**
      * Fired when this scope is not authorized
      * @event google-signin-aware-signed-out
      */
       properties: {
         /**
          * App package name for android over-the-air installs.
          * See the relevant [docs](https://developers.google.com/+/web/signin/android-app-installs)
          */
         appPackageName: {
           type: String,
@@ skipping 70 matching lines @@
          */
         labelSignin: {
           type: String,
           value: ''
         },
 
         _labelSignin: {
           type: String,
           computed: '_computeSigninLabel(labelSignin, width, _brand)'
         },
+
         /**
          * An optional label for the sign-out button.
          */
         labelSignout: {
           type: String,
           value: 'Sign out'
         },
 
         /**
          * If true, the button will be styled with a shadow.
          */
         raised: {
           type: Boolean,
           value: false
         },
 
         /**
          * The app activity types you want to write on behalf of the user
          * (e.g http://schemas.google.com/AddActivity)
          */
         requestVisibleActions: {
           type: String,
           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.
+         */
+        hostedDomain: {
+          type: String,
+          value: ''
+        },
+
+        /**
+         * Allows for offline `access_token` retrieval during the signin process.
+         */
+        offline: {
+          type: Boolean,
+          value: false
+        },
+
+        /**
+         * Forces a re-prompt, even if the user has already granted offline
+         * access to your application in the past. You only need one of
+         * `offline` and `offlineAlwaysPrompt`.
+         */
+        offlineAlwaysPrompt: {
+          type: Boolean,
+          value: false
+        },
+
+        /**
          * The scopes to provide access to (e.g https://www.googleapis.com/auth/drive)
          * and should be space-delimited.
          */
         scopes: {
           type: String,
           value: ''
         },
 
         /**
          * The theme to use for the button.
@@ skipping 155 matching lines @@
 
       _signOutKeyPress: function (e) {
         if (e.which == 13 || e.keyCode == 13 || e.which == 32 || e.keyCode == 32) {
           e.preventDefault();
           this.signOut();
         }
       }
     });
   }());
 </script>