Have content/ create and destroy its own threads.

content/browser/renderer_host/render_process_host.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/renderer_host/render_process_host.h"
 
 #include "base/command_line.h"
+#include "base/message_loop.h"
 #include "base/rand_util.h"
 #include "base/sys_info.h"
 #include "content/browser/browser_main.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/webui/web_ui_factory.h"
 #include "content/common/child_process_info.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
@@ skipping 221 matching lines @@
 
   // Now pick a random suitable renderer, if we have any.
   if (!suitable_renderers.empty()) {
     int suitable_count = static_cast<int>(suitable_renderers.size());
     int random_index = base::RandInt(0, suitable_count - 1);
     return suitable_renderers[random_index];
   }
 
   return NULL;
 }