Split a MetricsLogStore object out of MetricsLogManager.

components/metrics/metrics_log_store.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_METRICS_METRICS_LOG_STORE_H_
+#define COMPONENTS_METRICS_METRICS_LOG_STORE_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "components/metrics/log_store.h"
+#include "components/metrics/metrics_log.h"
+#include "components/metrics/persisted_logs.h"
+
+class PrefService;
+class PrefRegistrySimple;
+
+namespace metrics {
+
+// Interface for local storage of logs to be reported.

[rkaplow, 2017/02/20 21:24:13]

kind of strange wording, should you instead say this is an implementation using
PersistedLogs?

[Steven Holte, 2017/02/21 21:51:18]

Wrote a new description.

+class MetricsLogStore : public LogStore {
+ public:
+  MetricsLogStore(PrefService* local_state, size_t max_retransmit_size);
+  ~MetricsLogStore();
+
+  // At startup, prefs needs to be called with a list of all the pref names and
+  // types we'll be using.
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
+  // Saves |log_data| as the given type. Public to allow to push log created by
+  // external components.
+  void StoreLog(const std::string& log_data, MetricsLog::LogType log_type);
+
+  // metrics::LogStore implementation
+  bool has_unsent_logs() const override;
+  bool has_staged_log() const override;
+  const std::string& staged_log() const override;
+  const std::string& staged_log_hash() const override;
+  void StageNextLog() override;
+  void DiscardStagedLog() override;
+  void PersistUnsentLogs() const override;
+  void LoadPersistedUnsentLogs() override;
+
+  // Inspection methods for tests.
+  size_t ongoing_log_count() const { return ongoing_log_queue_.size(); }
+  size_t initial_log_count() const { return initial_log_queue_.size(); }
+
+ private:
+  // Tracks whether unsent logs (if any) have been loaded from the serializer.
+  bool unsent_logs_loaded_;
+
+  // Logs that have not yet been sent.

[rkaplow, 2017/02/20 21:24:13]

i'd say worth mentioning what the difference is-  what differentiates them and
why it needs to be seperate

[Steven Holte, 2017/02/21 21:51:19]

Done.

+  PersistedLogs initial_log_queue_;
+  PersistedLogs ongoing_log_queue_;
+
+  DISALLOW_COPY_AND_ASSIGN(MetricsLogStore);
+};
+
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_METRICS_LOG_STORE_H_