Add log date to the metrics log

components/metrics/metrics_log_manager.cc

Index: components/metrics/metrics_log_manager.cc
diff --git a/components/metrics/metrics_log_manager.cc b/components/metrics/metrics_log_manager.cc
index 415db78565618177b2e820984ee222efdbcc1dd8..fb091b4741506e0c851a49b4a73cd597d91c4494 100644
--- a/components/metrics/metrics_log_manager.cc
+++ b/components/metrics/metrics_log_manager.cc
@@ -49,7 +49,10 @@ MetricsLogManager::MetricsLogManager(PrefService* 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() {}