Roll Polymer

third_party/polymer/v1_0/components-chromium/app-layout/app-scroll-effects/effects/parallax-background-extracted.js

 /**
    * Vertically translate the background based on a factor of the scroll position.
    */
   Polymer.AppLayout.registerEffect('parallax-background', {
     /**
      * @param {{scalar: string}} config
      * @this Polymer.AppLayout.ElementWithBackground
      */
     setUp: function setUp(config) {
+      var fx = {};
       var scalar = parseFloat(config.scalar);
-
-      this._deltaBg = this.$.backgroundFrontLayer.offsetHeight - this.$.background.offsetHeight;
-      if (this._deltaBg === 0) {
+      fx.background = this._getDOMRef('background');
+      fx.backgroundFrontLayer = this._getDOMRef('backgroundFrontLayer');
+      fx.backgroundRearLayer = this._getDOMRef('backgroundRearLayer');
+      fx.deltaBg = fx.backgroundFrontLayer.offsetHeight - fx.background.offsetHeight;
+      if (fx.deltaBg === 0) {
         if (isNaN(scalar)) {
           scalar = 0.8;
         }
-        this._deltaBg = this._dHeight * scalar;
+        fx.deltaBg = this._dHeight * scalar;
       } else {
         if (isNaN(scalar)) {
           scalar = 1;
         }
-        this._deltaBg = this._deltaBg * scalar;
+        fx.deltaBg = fx.deltaBg * scalar;
+      }
+      this._fxParallaxBackground = fx;
+    },
+    /** @this Polymer.AppLayout.ElementWithBackground */
+    run: function run(p, y) {
+      var fx = this._fxParallaxBackground;
+      this.transform('translate3d(0px, ' + (fx.deltaBg * Math.min(1, p)) + 'px, 0px)', fx.backgroundFrontLayer);
+      if (fx.backgroundRearLayer) {
+        this.transform('translate3d(0px, ' + (fx.deltaBg * Math.min(1, p)) + 'px, 0px)', fx.backgroundRearLayer);
       }
     },
     /** @this Polymer.AppLayout.ElementWithBackground */
     tearDown: function tearDown() {
-      delete this._deltaBg;
-    },
-    /** @this Polymer.AppLayout.ElementWithBackground */
-    run: function run(p, y) {
-      this.transform('translate3d(0px, ' + (this._deltaBg * Math.min(1, p)) + 'px, 0px)', this.$.backgroundFrontLayer);
-      if (this.$.backgroundRearLayer) {
-        this.transform('translate3d(0px, ' + (this._deltaBg * Math.min(1, p)) + 'px, 0px)', this.$.backgroundRearLayer);
-      }
+      delete this._fxParallaxBackground;
     }
   });