Create a secondary file thread, FILE_USER_BLOCKING...

content/browser/browser_thread.cc

 // 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.
 
 #include "content/browser/browser_thread.h"
 
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "base/message_loop_proxy.h"
 #include "base/threading/thread_restrictions.h"
 
 // Friendly names for the well-known threads.
 static const char* browser_thread_names[BrowserThread::ID_COUNT] = {
   "",  // UI (name assembled in browser_main.cc).
   "Chrome_DBThread",  // DB
   "Chrome_WebKitThread",  // WEBKIT
   "Chrome_FileThread",  // FILE
   "Chrome_ProcessLauncherThread",  // PROCESS_LAUNCHER
   "Chrome_CacheThread",  // CACHE
+  "Chrome_AppCacheThread",  // APPCACHE

[rvargas (doing something else), 2011/10/21 19:46:17]

and here

   "Chrome_IOThread",  // IO
 #if defined(OS_CHROMEOS)
   "Chrome_WebSocketproxyThread",  // WEB_SOCKET_PROXY
 #endif
 };
 
 // An implementation of MessageLoopProxy to be used in conjunction
 // with BrowserThread.
 class BrowserThreadMessageLoopProxy : public base::MessageLoopProxy {
  public:
@@ skipping 301 matching lines @@
     } else {
       message_loop->PostNonNestableDelayedTask(from_here, task, delay_ms);
     }
   }
 
   if (!guaranteed_to_outlive_target_thread)
     lock_.Release();
 
   return !!message_loop;
 }