SGH / COMPONENTS

  iron-a11y-announcer
  ===================

  
  `iron-a11y-announcer` is a singleton element that is intended to add a11y
  to features that require on-demand announcement from screen readers. In
  order to make use of the announcer, it is best to request its availability
  in the announcing element.
  
  Example:
  
      Polymer({

        is: 'x-chatty',

        attached: function() {

          // This will create the singlton element if it has not

          // been created yet:
          Polymer.IronA11yAnnouncer.requestAvailability();
        }
      });

  After the `iron-a11y-announcer` has been made available, elements can
  make announces by firing bubbling `iron-announce` events.
  
  Example:
  
      this.fire('iron-announce', {
        text: 'This is an announcement!'
      }, { bubbles: true });

  Note: announcements are only audible if you have a screen reader enabled.