Measure usage metrics to prepare for adaptive fetching rates in M55

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 15 matching lines @@
     "ntp.request_throttler.suggestion_thumbnails.day";
 
 const char kDismissedRecentOfflineTabSuggestions[] =
     "ntp_suggestions.offline_pages.recent_tabs.dismissed_ids";
 const char kDismissedDownloadSuggestions[] =
     "ntp_suggestions.offline_pages.downloads.dismissed_ids";
 
 const char kBookmarksFirstM54Start[] =
     "ntp_suggestions.bookmarks.first_M54_start";
 
+const char kUserClassifierAverageHoursToOpenNTP[] =
+    "ntp_suggestions.user_classifier.average_hours_to_open_ntp";
+const char kUserClassifierAverageHoursToShowSuggestions[] =
+    "ntp_suggestions.user_classifier.average_hours_to_show_suggestions";
+const char kUserClassifierAverageHoursToUseSuggestions[] =
+    "ntp_suggestions.user_classifier.average_hours_to_use_suggestions";
+
+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