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

chrome/browser/net/errorpage_browsertest.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 <memory>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/path_service.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/browsing_data/browsing_data_helper.h"
 #include "chrome/browser/browsing_data/browsing_data_remover.h"
 #include "chrome/browser/browsing_data/browsing_data_remover_factory.h"
 #include "chrome/browser/net/net_error_diagnostics_dialog.h"
 #include "chrome/browser/net/url_request_mock_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search_engines/ui_thread_search_terms_data.h"
 #include "chrome/browser/ui/browser.h"
@@ skipping 1499 matching lines @@
                        Http09WeirdPortEnabled) {
   const char kHttp09Response[] = "JumboShrimp";
   ASSERT_TRUE(embedded_test_server()->Start());
   ui_test_utils::NavigateToURL(
       browser(), embedded_test_server()->GetURL(std::string("/echo-raw?") +
                                                 kHttp09Response));
   EXPECT_TRUE(IsDisplayingText(browser(), kHttp09Response));
 }
 
 }  // namespace