chrome/browser/resources/settings/controls/dialog_drawer.html

<link rel="import" href="chrome://resources/html/polymer.html">

<dom-module name="dialog-drawer">
  <template>
    <style>
      :host {
        --drawer-width: 256px;
        --transition-timing: 200ms ease;
        background-color: #fff;
        border: none;
        bottom: 0;
        left: calc(-1 * var(--drawer-width));
        margin: 0;
        overflow: hidden;
        padding: 0;
        position: absolute;
        top: 0;
        transition: left var(--transition-timing);
        width: var(--drawer-width);
      }

      :host,
      #container {
        height: 100%;
      }

      :host(.opening) {
        left: 0;
      }

      :host([align=right]) {
        left: auto;
        right: calc(-1 * var(--drawer-width));
        transition: right var(--transition-timing);
      }

      :host(.opening[align=right]) {
        right: 0;
      }

      :host::backdrop {
        background: rgba(0, 0, 0, 0.5);
        bottom: 0;
        left: 0;
        opacity: 0;
        position: absolute;
        right: 0;
        top: 0;
        transition: opacity var(--transition-timing);
      }

      :host(.opening)::backdrop {
        opacity: 1;
      }
    </style>
    <div id="container" on-tap="onContainerTap_">
      <content></content>
    </div>
  </template>
</dom-module>
<script src="dialog_drawer.js"></script>