Adding a "Learn more" link to the Google DNS selection

chrome/browser/resources/options/chromeos/internet_detail.css

 /* Copyright (c) 2012 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. */
 
 /* Force tab strip to extend to the left and right edges of the window. */
 #internet-details-content-area {
   -webkit-box-orient: vertical;
   display: -webkit-box;
   padding: 6px 0 0 0;
 }
@@ skipping 13 matching lines @@
   color: rgb(53, 174, 71);
 }
 
 
 /* Fix the height of the subpages so that the dialog does not resize when the
    user switches tabs. */
 #internet-details-content-area > .subpages-tab-contents {
   -webkit-box-flex: 1;
   -webkit-box-sizing: border-box;
   -webkit-padding-end: 10px;
-  height: 380px;
+  height: 390px;
   min-width: 480px;
   overflow-y: auto;
 }
 
 /* Avoid additional margins between text fields and controlled setting
    indicators as the fields in these dialogs have sufficient spacing around
    them already. */
 #internet-details-content-area
     input:-webkit-any([type='text'],[type='url'],:not([type])) +
     .controlled-setting-indicator {
@@ skipping 45 matching lines @@
   -webkit-margin-start: 24px;
   -webkit-transition: opacity 150ms ease-in-out;
   color: #bbb;
   font-style: italic;
 }
 
 .dns-display:not([selected]) {
   -webkit-transition: opacity 150ms ease-in-out;
   display: none;
 }