Update bower.json for Polymer elements and add PRESUBMIT.py

third_party/polymer/v1_0/components-chromium/neon-animation/animations/hero-animation-extracted.js

 
 
   Polymer({
 
     is: 'hero-animation',
 
     behaviors: [
       Polymer.NeonSharedElementAnimationBehavior
     ],
 
     configure: function(config) {
       var shared = this.findSharedElements(config);
       if (!shared) {
-        return null;
+        return;
       }
 
       var fromRect = shared.from.getBoundingClientRect();
       var toRect = shared.to.getBoundingClientRect();
 
       var deltaLeft = fromRect.left - toRect.left;
       var deltaTop = fromRect.top - toRect.top;
       var deltaWidth = fromRect.width / toRect.width;
       var deltaHeight = fromRect.height / toRect.height;
 
@@ skipping 13 matching lines @@
       var shared = this.findSharedElements(config);
       if (!shared) {
         return null;
       }
       shared.to.style.zIndex = '';
       shared.from.style.visibility = '';
     }
 
   });