Add enable-offlining-recent-pages feature switch.

components/offline_pages/offline_page_feature.cc

 // Copyright 2015 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/offline_page_feature.h"
 
 #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 {
 const char kOfflinePagesFieldTrialName[] = "OfflinePages";
 // The old experiment has only one mode to enable offline pages.
 const char kEnabledGroupName[] = "Enabled";
 // The new experiment supports two modes for offline pages.
 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.
   std::string group_name =
       base::FieldTrialList::FindFullName(kOfflinePagesFieldTrialName);
 
   // The old experiment 'Enabled' defaults to showing saved page.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableOfflinePages)) {
     return FeatureMode::ENABLED_AS_SAVED_PAGES;
@@ skipping 29 matching lines @@
   return version_info::IsOfficialBuild() ? FeatureMode::DISABLED
                                          : FeatureMode::ENABLED_AS_BOOKMARKS;
 }
 
 bool IsOfflinePagesEnabled() {
   FeatureMode mode = GetOfflinePageFeatureMode();
   return mode == FeatureMode::ENABLED_AS_BOOKMARKS ||
          mode == FeatureMode::ENABLED_AS_SAVED_PAGES;
 }
 
+bool IsOffliningRecentPagesEnabled() {
+  return  base::FeatureList::IsEnabled(kOffliningRecentPagesFeature) &&
+          IsOfflinePagesEnabled();
+}
+
 }  // namespace offline_pages
-
-#endif