code: function MaterialSnackbar(element) {
      this.element_ = element;
      this.textElement_ = this.element_.querySelector('.' + this.cssClasses_.MESSAGE);
      this.actionElement_ = this.element_.querySelector('.' + this.cssClasses_.ACTION);
      if (!this.textElement_) {
        throw new Error('There must be a message element for a snackbar.');
      }
      if (!this.actionElement_) {
        throw new Error('There must be an action element for a snackbar.');
      }
      this.active = false;
      this.actionHandler_ = undefined;
      this.message_ = undefined;
      this.actionText_ = undefined;
      this.timeoutID_ = undefined;
      this.queuedNotifications_ = [];
      this.setActionHidden_(true);
    }
docs: Class constructor for Snackbar MDL component.
  Implements MDL component design pattern defined at:
  https://github.com/jasonmayes/mdl-component-design-pattern
  
  @constructor
  @param {HTMLElement} element The element that will be upgraded.