Add new feature flag to enable background loader for downloads

components/offline_pages/offline_page_feature.h

Index: components/offline_pages/offline_page_feature.h
diff --git a/components/offline_pages/offline_page_feature.h b/components/offline_pages/offline_page_feature.h
index fee2325e260ed863fd340a0db7ae652ef8fc1cc3..3e60e7071afa9546145ce04b2504f48da462a6cf 100644
--- a/components/offline_pages/offline_page_feature.h
+++ b/components/offline_pages/offline_page_feature.h
@@ -15,6 +15,7 @@ extern const base::Feature kOffliningRecentPagesFeature;
 extern const base::Feature kOfflinePagesBackgroundLoadingFeature;
 extern const base::Feature kOfflinePagesCTFeature;
 extern const base::Feature kOfflinePagesSharingFeature;
+extern const base::Feature kBackgroundLoaderForDownloads;
 
 // Returns true if offline pages, as result of one or more offline features
 // being enabled, is enabled.
@@ -35,6 +36,8 @@ bool IsOfflinePagesCTEnabled();
 // Returns true if offline page sharing is enabled.
 bool IsOfflinePagesSharingEnabled();
 
+bool IsBackgroundLoaderForDownloadsEnabled();
+
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_FEATURE_H_>>>> Flag for Offline