MD Settings: Certificate manager, remove border from last certificate entry.

chrome/browser/resources/settings/certificate_manager_page/certificate_entry.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview An element that represents an SSL certificate entry.
  */
 Polymer({
   is: 'settings-certificate-entry',
 
   properties: {
     /** @type {!Certificate} */
     model: Object,
 
     /** @type {!settings.CertificateType} */
     certificateType: String,
   },
+
+  /**
+   * @param {number} index
+   * @return {boolean} Whether the given index corresponds to the last sub-node.
+   * @private
+   */
+  isLast_: function(index) {
+    return index == this.model.subnodes.length - 1;
+  },
 });