Add log date to the metrics log

components/metrics/metrics_log_manager.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_log_manager.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/strings/string_util.h"
@@ skipping 31 matching lines @@
     : unsent_logs_loaded_(false),
       initial_log_queue_(local_state,
                          prefs::kMetricsInitialLogs,
                          kInitialLogsPersistLimit,
                          kStorageByteLimitPerLogType,
                          0),
       ongoing_log_queue_(local_state,
                          prefs::kMetricsOngoingLogs,
                          kOngoingLogsPersistLimit,
                          kStorageByteLimitPerLogType,
-                         max_ongoing_log_size) {}
+                         max_ongoing_log_size) {
+  initial_log_queue_.MigrateFromOldFormat(prefs::kDeprecatedMetricsInitialLogs);

[Alexei Svitkine (slow), 2016/09/28 18:50:30]

I'm not sure we need an explicit migrate function. Just have the write function
always write in new format and things will migrate themselves whenever it's
updated.

+  ongoing_log_queue_.MigrateFromOldFormat(prefs::kDeprecatedMetricsOngoingLogs);
+}
 
 MetricsLogManager::~MetricsLogManager() {}
 
 void MetricsLogManager::BeginLoggingWithLog(std::unique_ptr<MetricsLog> log) {
   DCHECK(!current_log_);
   current_log_ = std::move(log);
 }
 
 void MetricsLogManager::FinishCurrentLog() {
   DCHECK(current_log_.get());
@@ skipping 58 matching lines @@
   ongoing_log_queue_.SerializeLogs();
 }
 
 void MetricsLogManager::LoadPersistedUnsentLogs() {
   initial_log_queue_.DeserializeLogs();
   ongoing_log_queue_.DeserializeLogs();
   unsent_logs_loaded_ = true;
 }
 
 }  // namespace metrics