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<link rel=“import” href=“../app-scroll-effects-behavior.html”>

<script>

/**
 * Toggles the shadow property in app-header when content is scrolled to create a sense of depth
 * between the element and the content underneath.
 */
Polymer.AppLayout.registerEffect('waterfall', {
  /**
   *  @this Polymer.AppLayout.ElementWithBackground
   */
  run: function run() {
    this.shadow = this.isOnScreen() && this.isContentBelow();
  }
});

</script>