Add a timeline view to about:net-internals.

chrome/test/data/webui/net_internals/log_util.js

 // 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.
 
 /**
  * Exports a log dump to a string and loads it.  Makes sure no errors occur,
  * and checks visibility of tabs aftwards.
  */
 netInternalsTest.test('netInternalsExportImportDump', function() {
   // Callback passed to |createLogDumpAsync|.  Tries to load the dumped log
   // file, and then checks tab visibility afterwards.
   // @param {string} logDumpText Log dump, as a string.
   function onLogDumpCreated(logDumpText) {
     expectEquals('Log loaded.', logutil.loadLogFile(logDumpText));
 
     var tabVisibilityState = {
       capture: false,
       export: false,
       import: true,
       proxy: true,
       events: true,
+      timeline: true,
       dns: true,
       sockets: true,
       spdy: true,
       httpCache: true,
       httpThrottling: false,
       serviceProviders: cr.isWindows,
       tests: false,
       hsts: false,
       logs: false,
       prerender: true
     };
 
     netInternalsTest.checkTabHandleVisibility(tabVisibilityState, false);
     testDone();
   }
 
   logutil.createLogDumpAsync('Log dump test', onLogDumpCreated);
 });