function showToast(parent, summary, linkUrl) {
  var toastDiv = $('<div>').addClass('alert-new-event event').attr('data-url', linkUrl);
  var toastDetails = $('<div>').addClass('event-details');
  var toastText = $('<div>')
                      .addClass('event-title')
                      .css('white-space', 'normal')
                      .text(chrome.i18n.getMessage('alert_new_event_added') + summary);

  toastDetails.append(toastText);
  toastDiv.append(toastDetails);

  $('.fab').fadeOut();
  parent.prepend(toastDiv).fadeIn();

  $('.alert-new-event').on('click', function() {
    chrome.tabs.create({'url': $(this).attr('data-url')});
  });

  return setTimeout(function() {
    $('.alert-new-event').fadeOut();
    $('.fab').fadeIn();
  }, browseraction.TOAST_FADE_OUT_DURATION_MS);
}
Listens for incoming requests from other pages of this extension and calls
the appropriate (local) functions.
@private