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// 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/sync_sessions/sync_sessions_metrics.h"
#include <algorithm>
#include <utility>
#include "base/logging.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/user_metrics.h"
#include "base/time/time.h"
#include "components/sessions/core/session_types.h"
#include "components/sync_sessions/sessions_sync_manager.h"
#include "components/sync_sessions/synced_session.h"
namespace sync_sessions {
// static
void SyncSessionsMetrics::RecordYoungestForeignTabAgeOnNTP(
SessionsSyncManager* sessions_sync_manager) {
if (sessions_sync_manager != nullptr) {
std::vector<const SyncedSession*> foreign_sessions;
sessions_sync_manager->GetAllForeignSessions(&foreign_sessions);
base::Time best(MaxTabTimestamp(foreign_sessions));
base::Time now(base::Time::Now());
// Don't emit metrics if the foreign tab is timestamped in the future. While
// the timestamp is set on a different machine, and we may lose some
// fraction of metrics to clock skew, we don't want the potential to have
// bad machines with clocks many hours off causing lots of seemingly 0
// second entries.
if (base::Time::UnixEpoch() < best && best <= now) {
UMA_HISTOGRAM_CUSTOM_COUNTS(
"Sync.YoungestForeignTabAgeOnNTP", (now - best).InSeconds(), 1,
base::TimeDelta::FromDays(14).InSeconds(), 100);
}
}
}
// static
base::Time SyncSessionsMetrics::MaxTabTimestamp(
const std::vector<const SyncedSession*>& sessions) {
// While Sessions are ordered by recency, windows and tabs are not. Because
// the timestamp of sessions are updated when windows/tabs are removed, we
// only need to search until all the remaining sessions are older than the
// most recent tab we've found so far.
base::Time best(base::Time::UnixEpoch());
for (const SyncedSession* session : sessions) {
if (session->modified_time < best) {
break;
}
for (const auto& key_value : session->windows) {
for (const auto& tab : key_value.second->tabs) {
best = std::max(best, tab->timestamp);
}
}
}
return best;
}
} // namespace sync_sessions
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