Remove some unused linked_ptr.h includes in c/b/extensions/api

chrome/browser/extensions/api/file_system/file_system_api.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 "chrome/browser/extensions/api/file_system/file_system_api.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <set>
 #include <utility>
 #include <vector>
 
 #include "apps/saved_files_service.h"
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
-#include "base/memory/linked_ptr.h"
 #include "base/memory/ptr_util.h"
 #include "base/path_service.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/value_conversions.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/api/file_handlers/app_file_handler_util.h"
@@ skipping 1416 matching lines @@
     return RespondNow(Error(kNotSupportedOnNonKioskSessionError));
   std::vector<api::file_system::Volume> result_volume_list;
   FillVolumeList(chrome_details_.GetProfile(), &result_volume_list);
 
   return RespondNow(ArgumentList(
       api::file_system::GetVolumeList::Results::Create(result_volume_list)));
 }
 #endif
 
 }  // namespace extensions