RemoteContentSuggestions: Stores the time of the last successful background fetch in a pref

components/ntp_snippets/pref_names.cc

 // Copyright 2016 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/ntp_snippets/pref_names.h"
 
 namespace ntp_snippets {
 namespace prefs {
 
 const char kEnableSnippets[] = "ntp_snippets.enable";
@@ skipping 23 matching lines @@
 const char kDismissedAssetDownloadSuggestions[] =
     "ntp_suggestions.downloads.assets.dismissed_ids";
 const char kDismissedRecentOfflineTabSuggestions[] =
     "ntp_suggestions.offline_pages.recent_tabs.dismissed_ids";
 const char kDismissedOfflinePageDownloadSuggestions[] =
     "ntp_suggestions.downloads.offline_pages.dismissed_ids";
 const char kDismissedForeignSessionsSuggestions[] =
     "ntp_suggestions.foreign_sessions.dismissed_ids";
 const char kDismissedCategories[] = "ntp_suggestions.dismissed_categories";
 
+const char kLastSuccessfulBackgroundFetchTime[] =
+    "ntp_suggestions.remote.last_successful_background_fetch_time";
+
 const char kUserClassifierAverageNTPOpenedPerHour[] =
     "ntp_suggestions.user_classifier.average_ntp_opened_per_hour";
 const char kUserClassifierAverageSuggestionsShownPerHour[] =
     "ntp_suggestions.user_classifier.average_suggestions_shown_per_hour";
 const char kUserClassifierAverageSuggestionsUsedPerHour[] =
     "ntp_suggestions.user_classifier.average_suggestions_used_per_hour";
 
 const char kUserClassifierLastTimeToOpenNTP[] =
     "ntp_suggestions.user_classifier.last_time_to_open_ntp";
 const char kUserClassifierLastTimeToShowSuggestions[] =
     "ntp_suggestions.user_classifier.last_time_to_show_suggestions";
 const char kUserClassifierLastTimeToUseSuggestions[] =
     "ntp_suggestions.user_classifier.last_time_to_use_suggestions";
 
 }  // namespace prefs
 }  // namespace ntp_snippets