Create skeleton for the Prefetching store and initial pipeline step.

components/offline_pages/core/prefetch/prefetch_item.cc

 // 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.
 
 #include "components/offline_pages/core/prefetch/prefetch_item.h"
 
 namespace offline_pages {
 
 PrefetchItem::PrefetchItem() = default;
 
 PrefetchItem::PrefetchItem(const PrefetchItem& other) = default;
 
 PrefetchItem::~PrefetchItem(){};
 
 bool PrefetchItem::operator==(const PrefetchItem& other) const {
-  return guid == other.guid && client_name_space == other.client_name_space &&
-         client_id == other.client_id && state == other.state &&
-         url == other.url && final_archived_url == other.final_archived_url &&
+  return guid == other.guid && client_id == other.client_id &&
+         state == other.state && url == other.url &&
+         final_archived_url == other.final_archived_url &&
          request_archive_attempt_count == other.request_archive_attempt_count &&
          operation_name == other.operation_name &&
          archive_body_name == other.archive_body_name &&
          archive_body_length == other.archive_body_length &&
          creation_time == other.creation_time &&
          freshness_time == other.freshness_time &&
          error_code == other.error_code;
 }
 
 bool PrefetchItem::operator!=(const PrefetchItem& other) const {
   return !(*this == other);
 }
 
 }  // namespace offline_pages