MD Settings: About page, show error messages with <br> and <pre> tags.

chrome/browser/resources/settings/about_page/about_page.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-about-page' contains version and OS related
  * information.
  */
 Polymer({
   is: 'settings-about-page',
@@ skipping 259 matching lines @@
           // NOTE(dbeam): some platforms (i.e. Mac) always send 0% while
           // updating (they don't support incremental upgrade progress). Though
           // it's certainly quite possible to validly end up here with 0% on
           // platforms that support incremental progress, nobody really likes
           // seeing that they're 0% done with something.
           return this.i18n('aboutUpgradeUpdatingPercent', progressPercent);
         }
         return this.i18n('aboutUpgradeUpdating');
       default:
         function formatMessage(msg) {
-          return '<div>' +
-              parseHtmlSubset('<b>' + msg + '</b>').firstChild.innerHTML +
-              '</div>';
+          return parseHtmlSubset(
+              '<b>' + msg + '</b>', ['br', 'pre']).firstChild.innerHTML;
         }
         var result = '';
         var message = this.currentUpdateStatusEvent_.message;
-        if (!!message)
+        if (message)
           result += formatMessage(message);
         var connectMessage = this.currentUpdateStatusEvent_.connectionTypes;
-        if (!!connectMessage)
-          result += formatMessage(connectMessage);
+        if (connectMessage)
+          result += '<div>' + formatMessage(connectMessage) + '</div>';
         return result;
     }
   },
 
   /**
    * @return {?string}
    * @private
    */
   getIcon_: function() {
     // If this platform has reached the end of the line, display an error icon
@@ skipping 109 matching lines @@
     });
   },
 
 // <if expr="_google_chrome">
   /** @private */
   onReportIssueTap_: function() {
     this.aboutBrowserProxy_.openFeedbackDialog();
   },
 // </if>
 });