function MdLiveAnnouncer($timeout) {
  /** @private @const @type {!angular.$timeout} */
  this._$timeout = $timeout;

  /** @private @const @type {!HTMLElement} */
  this._liveElement = this._createLiveElement();

  /** @private @const @type {!number} */
  this._announceTimeout = 100;
}
@ngdoc service
@name $mdLiveAnnouncer
@module material.core.liveannouncer

@description

Service to announce messages to supported screenreaders.

> The `$mdLiveAnnouncer` service is internally used for components to provide proper accessibility.

<hljs lang="js">
  module.controller('AppCtrl', function($mdLiveAnnouncer) {
    // Basic announcement (Polite Mode)
    $mdLiveAnnouncer.announce('Hey Google');

    // Custom announcement (Assertive Mode)
    $mdLiveAnnouncer.announce('Hey Google', 'assertive');
  });
</hljs>