Improve extension settings accessibility.

chrome/browser/resources/options/extension_settings.css

 /*
 Copyright (c) 2011 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.
 */
 
 .details-view {
   -webkit-padding-end: 10px;
 }
 
@@ skipping 246 matching lines @@
 
 #get-more-extensions-container {
   display: -webkit-box;
 }
 
 #get-more-extensions {
   padding-top: 5px;
   font-size: 15px;
   -webkit-padding-start: 10px;
 }
+
+/* Support full keyboard accessibility without making things ugly
+   for users who click, by hiding some focus outlines when the user
+   clicks anywhere, but showing them when the user presses any key. */
+body.hide-some-focus-outlines .extension-zippy-container {
+  outline: none;
+}