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

chrome/browser/ui/desktop_ios_promotion/sms_service.h

 // Copyright 2017 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.
 
 #ifndef CHROME_BROWSER_UI_DESKTOP_IOS_PROMOTION_SMS_SERVICE_H_
 #define CHROME_BROWSER_UI_DESKTOP_IOS_PROMOTION_SMS_SERVICE_H_
 
 #include <stddef.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
+#include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "url/gurl.h"
 
 namespace net {
 class URLRequestContextGetter;
 }
 
@@ skipping 75 matching lines @@
   // Pending expiration requests to be canceled if not complete by profile
   // shutdown.
   std::map<Request*, std::unique_ptr<Request>> pending_requests_;
 
   base::WeakPtrFactory<SMSService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SMSService);
 };
 
 #endif  // CHROME_BROWSER_UI_DESKTOP_IOS_PROMOTION_SMS_SERVICE_H_