Fix vertical overflow in about:media-internals

content/browser/resources/media/media_internals.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. */
 
 html,
 body,
 #container {
   margin: 0;
   padding: 0;
   width: 100%;
   height: 100%;
   font-family:Arial;
 }
 
 tabbox {
-  margin-top: 10px;
+  padding-top: 10px;
 }
 
 tab {
   -webkit-user-select: none;
 }
 
 body tabpanels {
   box-shadow: none;
 }
 
@@ skipping 172 matching lines @@
 
 .no-players-selected #players .property-wrapper,
 .no-players-selected #players #log-wrapper {
   display: none;
 }
 
 .no-components-selected #audio .property-wrapper {
   display: none;
 }