Create Ukm ReportingService implementation.

components/metrics/metrics_pref_names.cc

 // Copyright 2014 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/metrics/metrics_pref_names.h"
 
 namespace metrics {
 namespace prefs {
 
 // Set once, to the current epoch time, on the first run of chrome on this
@@ skipping 172 matching lines @@
     "user_experience_metrics.stability.version_mismatch_count";
 
 // The keys below are strictly increasing counters over the lifetime of
 // a chrome installation. They are (optionally) sent up to the uninstall
 // survey in the event of uninstallation.
 const char kUninstallLaunchCount[] = "uninstall_metrics.launch_count";
 const char kUninstallMetricsPageLoadCount[] =
     "uninstall_metrics.page_load_count";
 const char kUninstallMetricsUptimeSec[] = "uninstall_metrics.uptime_sec";
 
+// Dictionary for measuring cellular data used by UKM service during last 7
+// days.
+const char kUkmCellDataUse[] = "user_experience_metrics.ukm_cell_datause";
+
 // Dictionary for measuring cellular data used by UMA service during last 7
 // days.
 const char kUmaCellDataUse[] = "user_experience_metrics.uma_cell_datause";
 
 // Dictionary for measuring cellular data used by user including chrome services
 // per day.
 const char kUserCellDataUse[] = "user_experience_metrics.user_call_datause";
 
 }  // namespace prefs
 }  // namespace metrics