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

chrome/browser/task_manager/sampling/shared_sampler_win_unittest.cc

 // Copyright 2016 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/task_manager/sampling/shared_sampler.h"
 
 #include <windows.h>
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/sequenced_task_runner.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/time/time.h"
 #include "chrome/browser/task_manager/sampling/shared_sampler_win_defines.h"
 #include "chrome/browser/task_manager/task_manager_observer.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace task_manager {
 
 // This test class drives SharedSampler in a way similar to the real
@@ skipping 221 matching lines @@
   EXPECT_EQ(REFRESH_TYPE_IDLE_WAKEUPS | REFRESH_TYPE_PHYSICAL_MEMORY |
                 REFRESH_TYPE_START_TIME | REFRESH_TYPE_CPU_TIME,
             finished_refresh_type());
 
   EXPECT_EQ(1024ll, physical_bytes());
 
   SharedSampler::SetQuerySystemInformationForTest(nullptr);
 }
 
 }  // namespace task_manager