MD Settings: Certificate manager, implement importing CA certificate.

chrome/browser/resources/settings/certificate_manager_page/certificate_subentry.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 settings-certificate-subentry represents an SSL certificate
  * sub-entry.
  */
 
 /**
  * The payload of the certificate-action event that is emitted from this
  * component.
  * @typedef {{
  *   action: !settings.CertificateAction,
- *   subnode: ?CertificateSubnode,
+ *   subnode: null|CertificateSubnode|NewCertificateSubNode,
  *   certificateType: !settings.CertificateType
  * }}
  */
 var CertificateActionEventDetail;
 
 cr.define('settings', function() {
   /**
    * Enumeration of actions that require a popup menu to be shown to the user.
    * @enum {number}
    */
@@ skipping 121 matching lines @@
    */
   canEdit_: function(certificateType) {
     return this.certificateType == settings.CertificateType.CA;
   },
 
   /** @private */
   closePopupMenu_: function() {
     this.$$('iron-dropdown').close();
   },
 });