Have content/ create and destroy its own threads.

chrome/browser/printing/cloud_print/cloud_print_proxy_service.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/printing/cloud_print/cloud_print_proxy_service.h"
 
 #include <stack>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_setup_flow.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/service/service_process_control.h"
 #include "chrome/browser/ui/browser_list.h"
@@ skipping 184 matching lines @@
   proxy_id_ = proxy_info.proxy_id;
   profile_->GetPrefs()->SetString(
       prefs::kCloudPrintEmail,
       proxy_info.enabled ? proxy_info.email : std::string());
 }
 
 bool CloudPrintProxyService::InvokeServiceTask(const base::Closure& task) {
   ServiceProcessControl::GetInstance()->Launch(task, base::Closure());
   return true;
 }