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

third_party/polymer/v1_0/components-chromium/iron-collapse/iron-collapse-extracted.js

 
 
   Polymer({
 
     is: 'iron-collapse',
 
     properties: {
 
       /**
        * If true, the orientation is horizontal; otherwise is vertical.
@@ skipping 15 matching lines @@
         type: Boolean,
         value: false,
         notify: true,
         observer: '_openedChanged'
       }
 
     },
 
     hostAttributes: {
       role: 'group',
-      'aria-expanded': 'false',
-      tabindex: 0
+      'aria-expanded': 'false'
     },
 
     listeners: {
       transitionend: '_transitionEnd'
     },
 
     ready: function() {
       // Avoid transition at the beginning e.g. page loads and enable
       // transitions only after the element is rendered and ready.
       this._enableTransition = true;
@@ skipping 60 matching lines @@
       this.enableTransition(false);
     },
 
     _calcSize: function() {
       return this.getBoundingClientRect()[this.dimension] + 'px';
     },
 
 
   });