Remove details strings used by iframes on network error pages

components/neterror/resources/neterror.css

 /* Copyright 2013 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. */
 
 /* Don't use the main frame div when the error is in a subframe. */
 html[subframe] #main-frame-error {
   display: none;
 }
 
 /* Don't use the subframe error div when the error is in a main frame. */
@@ skipping 250 matching lines @@
 
 #sub-frame-error {
   -webkit-align-items: center;
   background-color: #DDD;
   display: -webkit-flex;
   -webkit-flex-flow: column;
   height: 100%;
   -webkit-justify-content: center;
   left: 0;
   position: absolute;
+  text-align: center;

[edwardjung, 2016/06/23 18:52:04]

Centres the icon following the switch from an image tag to div.

   top: 0;
   transition: background-color .2s ease-in-out;
   width: 100%;
 }
 
 #sub-frame-error:hover {
   background-color: #EEE;
 }
 
 #sub-frame-error .icon-generic {
@@ skipping 196 matching lines @@
     overflow: inherit;
     padding: 0 8px;
   }
 }
 
 @media (max-width: 120px) {
   button {
     width: auto;
   }
 }