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

chrome/browser/ui/webui/print_preview/printer_capabilities_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 <memory>
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/run_loop.h"
+#include "base/task_runner_util.h"
 #include "base/test/values_test_util.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/ui/webui/print_preview/printer_capabilities.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "printing/backend/test_print_backend.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace {
 
 void SettingsReply(std::unique_ptr<base::DictionaryValue>* out,
@@ skipping 93 matching lines @@
       GetSettingsSynchronous(printer_name, basic_info);
 
   // verify settings were created
   ASSERT_TRUE(settings_dictionary);
 
   // verify that capabilities is an empty dictionary
   base::DictionaryValue* caps_dict;
   ASSERT_TRUE(settings_dictionary->GetDictionary("capabilities", &caps_dict));
   EXPECT_TRUE(caps_dict->empty());
 }