Split a MetricsLogStore object out of MetricsLogManager.

components/metrics/persisted_logs_metrics_impl.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/metrics/persisted_logs_metrics_impl.h"
 
 #include "base/metrics/histogram_macros.h"
 
 namespace metrics {
 
-PersistedLogs::LogReadStatus
-PersistedLogsMetricsImpl::RecordLogReadStatus(
-    PersistedLogs::LogReadStatus status) {
-  UMA_HISTOGRAM_ENUMERATION("PrefService.PersistentLogRecallProtobufs",
-                            status, PersistedLogs::END_RECALL_STATUS);
-  return status;
+void PersistedLogsMetricsImpl::RecordLogReadStatus(
+    PersistedLogsMetrics::LogReadStatus status) {
+  UMA_HISTOGRAM_ENUMERATION("PrefService.PersistentLogRecallProtobufs", status,
+                            PersistedLogsMetrics::END_RECALL_STATUS);
 }
 
 void PersistedLogsMetricsImpl::RecordCompressionRatio(
     size_t compressed_size, size_t original_size) {
   UMA_HISTOGRAM_PERCENTAGE(
       "UMA.ProtoCompressionRatio",
       static_cast<int>(100 * compressed_size / original_size));
 }
 
 void PersistedLogsMetricsImpl::RecordDroppedLogSize(size_t size) {
   UMA_HISTOGRAM_COUNTS("UMA.Large Accumulated Log Not Persisted",
                        static_cast<int>(size));
 }
 
 void PersistedLogsMetricsImpl::RecordDroppedLogsNum(int dropped_logs_num) {
   UMA_HISTOGRAM_COUNTS("UMA.UnsentLogs.Dropped", dropped_logs_num);
 }
 
 }  // namespace metrics