systrace/catapult/third_party/polymer/components/neon-animation/neon-shared-element-animation-behavior.html

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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="neon-animation-behavior.html">

<script>

  /**
   * Use `Polymer.NeonSharedElementAnimationBehavior` to implement shared element animations.
   * @polymerBehavior Polymer.NeonSharedElementAnimationBehavior
   */
  Polymer.NeonSharedElementAnimationBehaviorImpl = {

    properties: {

      /**
       * Cached copy of shared elements.
       */
      sharedElements: {
        type: Object
      }

    },

    /**
     * Finds shared elements based on `config`.
     */
    findSharedElements: function(config) {
      var fromPage = config.fromPage;
      var toPage = config.toPage;
      if (!fromPage || !toPage) {
        console.warn(this.is + ':', !fromPage ? 'fromPage' : 'toPage', 'is undefined!');
        return null;
      };

      if (!fromPage.sharedElements || !toPage.sharedElements) {
        console.warn(this.is + ':', 'sharedElements are undefined for', !fromPage.sharedElements ? fromPage : toPage);
        return null;
      };

      var from = fromPage.sharedElements[config.id]
      var to = toPage.sharedElements[config.id];

      if (!from || !to) {
        console.warn(this.is + ':', 'sharedElement with id', config.id, 'not found in', !from ? fromPage : toPage);
        return null;
      }

      this.sharedElements = {
        from: from,
        to: to
      };
      return this.sharedElements;
    }

  };

  /** @polymerBehavior Polymer.NeonSharedElementAnimationBehavior */
  Polymer.NeonSharedElementAnimationBehavior = [
    Polymer.NeonAnimationBehavior,
    Polymer.NeonSharedElementAnimationBehaviorImpl
  ];

</script>