Split a MetricsLogStore object out of MetricsLogManager.

components/ukm/persisted_logs_metrics_impl.h

 // Copyright 2017 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.
 
 #ifndef COMPONENTS_UKM_PERSISTED_LOGS_METRICS_IMPL_H_
 #define COMPONENTS_UKM_PERSISTED_LOGS_METRICS_IMPL_H_
 
 #include "base/macros.h"
 #include "components/metrics/persisted_logs_metrics.h"
 
 namespace ukm {
 
 // Implementation for recording metrics from PersistedLogs.
 class PersistedLogsMetricsImpl : public metrics::PersistedLogsMetrics {
  public:
   PersistedLogsMetricsImpl();
   ~PersistedLogsMetricsImpl() override;
 
   // metrics::PersistedLogsMetrics:
-  metrics::PersistedLogs::LogReadStatus RecordLogReadStatus(
-      metrics::PersistedLogs::LogReadStatus status) override;
+  void RecordLogReadStatus(
+      metrics::PersistedLogsMetrics::LogReadStatus status) override;
   void RecordCompressionRatio(size_t compressed_size,
                               size_t original_size) override;
   void RecordDroppedLogSize(size_t size) override;
   void RecordDroppedLogsNum(int dropped_logs_num) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PersistedLogsMetricsImpl);
 };
 
 }  // namespace ukm
 
 #endif  // COMPONENTS_UKM_PERSISTED_LOGS_METRICS_IMPL_H_