chromium/chrome/browser/resources/side_panel/read_anything/menus/simple_action_menu.html

<style include="read-anything-toolbar">
  .has-icon-false {
    display: none;
  }

  .has-icon-true {
    display: inline-flex;
  }

  .check-mark-showing-true {
    visibility: visible;
  }

  .check-mark-showing-false {
    visibility: hidden;
  }
</style>

<cr-lazy-render id="lazyMenu">
  <template>
    <cr-action-menu accessibility-label="[[label]]"
        role-description="$i18n{menu}"
        tabindex="-1">
      <template is="dom-repeat" items="[[menuItems]]"
          index-as="index"
          initial-count="[[initialCount]]">
        <button class="dropdown-item" on-click="onClick_">
          <cr-icon class$="button-image check-mark
              check-mark-showing-[[isItemSelected_(index, currentSelectedIndex)]]"
              icon="read-anything-20:check-mark"
              aria-label="$i18n{selected}">
          </cr-icon>
          <cr-icon class$="button-image has-icon-[[doesItemHaveIcon_(item)]]"
              icon="[[itemIcon_(item)]]">
          </cr-icon>
          [[item.title]]
        </button>
      </template>
    </cr-action-menu>
  </template>
</cr-lazy-render>