[Offline Pages] Removes the deprecated IsOfflinePages synthetic flag since no uses of it remain.

components/offline_pages/offline_page_feature.cc

Index: components/offline_pages/offline_page_feature.cc
diff --git a/components/offline_pages/offline_page_feature.cc b/components/offline_pages/offline_page_feature.cc
index bee289a57ceae98ca845f6f4aca485c140bcbcf3..c469846124d11c98ca28a60808c2173f253e38d4 100644
--- a/components/offline_pages/offline_page_feature.cc
+++ b/components/offline_pages/offline_page_feature.cc
@@ -32,12 +32,6 @@ const base::Feature kOfflinePagesSharingFeature{
 const base::Feature kBackgroundLoaderForDownloadsFeature{
     "BackgroundLoadingForDownloads", base::FEATURE_ENABLED_BY_DEFAULT};
 
-bool IsOfflinePagesEnabled() {
-  return IsOfflineBookmarksEnabled() || IsOffliningRecentPagesEnabled() ||
-         IsOfflinePagesBackgroundLoadingEnabled() ||
-         IsOfflinePagesCTEnabled() || IsOfflinePagesSharingEnabled();
-}
-
 bool IsOfflineBookmarksEnabled() {
   return base::FeatureList::IsEnabled(kOfflineBookmarksFeature);
 }