Reland of move header dependencies from sequence_checker.h to sequenced_worker_pool.h

chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc

 // Copyright 2015 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/android/webapps/add_to_homescreen_data_fetcher.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/strings/string16.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/android/offline_pages/offline_page_utils.h"
 #include "chrome/browser/android/shortcut_helper.h"
 #include "chrome/browser/android/webapk/webapk_web_manifest_checker.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/installable/installable_manager.h"
 #include "chrome/browser/manifest/manifest_icon_selector.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/web_application_info.h"
@@ skipping 309 matching lines @@
 void AddToHomescreenDataFetcher::NotifyObserver(const SkBitmap& primary_icon) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   if (!web_contents() || !weak_observer_ || is_icon_saved_)
     return;
 
   is_icon_saved_ = true;
   primary_icon_ = primary_icon;
   is_ready_ = true;
   weak_observer_->OnDataAvailable(shortcut_info_, primary_icon_, badge_icon_);
 }