Add enable-offlining-recent-pages feature switch.

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 ed390b8815e0abe9990d76c5fa0f1bfefbb11ebb..ab00925cf73069a62c29a4fdd30c6057a5374372 100644
--- a/components/offline_pages/offline_page_feature.cc
+++ b/components/offline_pages/offline_page_feature.cc
@@ -7,14 +7,13 @@
 #include <string>
 
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_util.h"
 #include "build/build_config.h"
 #include "components/offline_pages/offline_page_switches.h"
 #include "components/version_info/version_info.h"
 
-#if defined(OS_ANDROID)
-
 namespace offline_pages {
 
 namespace {
@@ -26,6 +25,10 @@ const char kEnabledAsBookmarksGroupName[] = "EnabledAsBookmarks";
 const char kEnabledAsSavedPagesGroupName[] = "EnabledAsSavedPages";
 }  // namespace
 
+const base::Feature kOffliningRecentPagesFeature {
+   "offline-recent-pages", base::FEATURE_DISABLED_BY_DEFAULT
+};
+
 FeatureMode GetOfflinePageFeatureMode() {
   // Note: It's important to query the field trial state first, to ensure that
   // UMA reports the correct group.
@@ -75,6 +78,9 @@ bool IsOfflinePagesEnabled() {
          mode == FeatureMode::ENABLED_AS_SAVED_PAGES;
 }
 
-}  // namespace offline_pages
+bool IsOffliningRecentPagesEnabled() {
+  return  base::FeatureList::IsEnabled(kOffliningRecentPagesFeature) &&
+          IsOfflinePagesEnabled();
+}
 
-#endif
+}  // namespace offline_pages