Add missing #include around sequenced_worker_pool.h in //chrome

chrome/browser/prerender/prerender_test_utils.cc

 // 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.
 
 #include "chrome/browser/prerender/prerender_test_utils.h"
 
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/loader/chrome_resource_dispatcher_host_delegate.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/safe_browsing/local_database_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/grit/generated_resources.h"
 #include "chrome/test/base/ui_test_utils.h"
@@ skipping 777 matching lines @@
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   std::unique_ptr<net::URLRequestInterceptor> interceptor(
       new HangingFirstRequestInterceptor(file, callback));
   net::URLRequestFilter::GetInstance()->AddUrlInterceptor(
       url, std::move(interceptor));
 }
 
 }  // namespace test_utils
 
 }  // namespace prerender