Create a secondary file thread, FILE_USER_BLOCKING...

chrome/browser/chrome_browser_main.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 "chrome/browser/chrome_browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 297 matching lines @@
 }
 
 // Creates key child threads. We need to do this explicitly since
 // BrowserThread::PostTask silently deletes a posted task if the target message
 // loop isn't created.
 void CreateChildThreads(BrowserProcessImpl* process) {
   process->db_thread();
   process->file_thread();
   process->process_launcher_thread();
   process->cache_thread();
+  process->appcache_thread();

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

Do you mind creating this thread before the cache thread. I'd prefer to keep the
cache and io thread together so that they are easier to identify on crash dumps.

[michaeln, 2011/10/21 19:52:12]

will do (ditto other necessary places)

   process->io_thread();
 #if defined(OS_CHROMEOS)
   process->web_socket_proxy_thread();
 #endif
   // Create watchdog thread after creating all other threads because it will
   // watch the other threads and they must be running.
   process->watchdog_thread();
 }
 
 // Returns the new local state object, guaranteed non-NULL.
@@ skipping 1764 matching lines @@
   if (env->GetVar(chrome::kPreReadEnvironmentVariable, &pre_read) &&
       (pre_read == "0" || pre_read == "1")) {
     std::string uma_name(name);
     uma_name += "_PreRead";
     uma_name += pre_read == "1" ? "Enabled" : "Disabled";
     AddPreReadHistogramTime(uma_name.c_str(), time);
   }
 #endif
 #endif
 }