Remove stale-while-revalidate experimental implementation.

chrome/browser/resources/net_internals/source_entry.js

 // 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.
 
 var SourceEntry = (function() {
   'use strict';
 
   /**
    * A SourceEntry gathers all log entries with the same source.
    *
@@ skipping 64 matching lines @@
 
       if (e.params == undefined) {
         return;
       }
 
       switch (e.source.type) {
         case EventSourceType.URL_REQUEST:
         // TODO(ricea): Remove SOCKET_STREAM after M41 is released.
         case EventSourceType.SOCKET_STREAM:
         case EventSourceType.HTTP_STREAM_JOB:
-        case EventSourceType.ASYNC_REVALIDATION:
           this.description_ = e.params.url;
           break;
         case EventSourceType.CONNECT_JOB:
           this.description_ = e.params.group_name;
           break;
         case EventSourceType.HOST_RESOLVER_IMPL_JOB:
         case EventSourceType.HOST_RESOLVER_IMPL_PROC_TASK:
           this.description_ = e.params.host;
           break;
         case EventSourceType.DISK_CACHE_ENTRY:
@@ skipping 245 matching lines @@
           this.entries_,
           SourceTracker.getInstance().getPrivacyStripping(),
           SourceTracker.getInstance().getUseRelativeTimes() ?
               timeutil.getBaseTime() : 0,
           Constants.clientInfo.numericDate);
     },
   };
 
   return SourceEntry;
 })();