Add a timeline view to about:net-internals.

chrome/browser/resources/net_internals/main.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.
 */
 
 /* TODO(eroman): Split this file up, so the styles are defined close to where
                  they are used. For instance, the proxy tab styles should
                  either be part of proxy_view.html, or proxy_view.css. Only
                  common styles should be declared here */
 
 * {
   box-sizing: border-box;
   -moz-box-sizing: border-box;
 }
 body {
   font-family: sans-serif;
 }
 
 /* This class is used to create the splitter widget in
    ResizbleVerticalSplitView */
 .vertical-splitter {
   background: #bfbfbf;
   border-left: 1px inset black;
   border-right: 1px solid black;
-  position:absolute;
+  position: absolute;
   width: 8px;
   cursor: col-resize;
   user-select: none;
 }
 
 .logSourceEntry {
   margin: 5px;
 }
 
 .logSourceEntry * p {
@@ skipping 68 matching lines @@
   background: red;
   color: #eee;
   padding: 4px;
 }
 
 #status-view-for-file {
   background: #88c;
   color: #eee;
   padding: 4px;
 }