metrics_service_unittest.cc

// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/metrics/metrics_service.h"

#include <stdint.h>

#include <algorithm>
#include <memory>
#include <string>
#include <string_view>

#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "base/functional/bind.h"
#include "base/memory/raw_ptr.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_snapshot_manager.h"
#include "base/metrics/metrics_hashes.h"
#include "base/metrics/statistics_recorder.h"
#include "base/metrics/user_metrics.h"
#include "base/strings/to_string.h"
#include "base/task/single_thread_task_runner.h"
#include "base/test/metrics/histogram_tester.h"
#include "base/test/task_environment.h"
#include "base/threading/platform_thread.h"
#include "build/build_config.h"
#include "components/metrics/clean_exit_beacon.h"
#include "components/metrics/client_info.h"
#include "components/metrics/cloned_install_detector.h"
#include "components/metrics/environment_recorder.h"
#include "components/metrics/log_decoder.h"
#include "components/metrics/metrics_log.h"
#include "components/metrics/metrics_pref_names.h"
#include "components/metrics/metrics_scheduler.h"
#include "components/metrics/metrics_state_manager.h"
#include "components/metrics/metrics_upload_scheduler.h"
#include "components/metrics/stability_metrics_helper.h"
#include "components/metrics/test/test_enabled_state_provider.h"
#include "components/metrics/test/test_metrics_provider.h"
#include "components/metrics/test/test_metrics_service_client.h"
#include "components/metrics/unsent_log_store_metrics_impl.h"
#include "components/prefs/testing_pref_service.h"
#include "components/variations/active_field_trials.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/metrics_proto/chrome_user_metrics_extension.pb.h"
#include "third_party/metrics_proto/system_profile.pb.h"
#include "third_party/zlib/google/compression_utils.h"

namespace metrics {
namespace {

const char kTestPrefName[] = "TestPref";

#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_IOS)
const char kBeforeBackgroundHistogram[] = "Test.BeforeBackground";
const char kBeforeForegroundHistogram[] = "Test.BeforeForeground";
#endif  // BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_IOS)

class TestUnsentLogStore : public UnsentLogStore {
 public:
  explicit TestUnsentLogStore(PrefService* service)
      : UnsentLogStore(std::make_unique<UnsentLogStoreMetricsImpl>(),
                       service,
                       kTestPrefName,
                       nullptr,
                       // Set to 3 so logs are not dropped in the test.
                       UnsentLogStore::UnsentLogStoreLimits{
                           .min_log_count = 3,
                       },
                       /*signing_key=*/std::string(),
                       /*logs_event_manager=*/nullptr) {}
  ~TestUnsentLogStore() override = default;

  TestUnsentLogStore(const TestUnsentLogStore&) = delete;
  TestUnsentLogStore& operator=(const TestUnsentLogStore&) = delete;

  static void RegisterPrefs(PrefRegistrySimple* registry) {
    registry->RegisterListPref(kTestPrefName);
  }
};

// Returns true if |id| is present in |proto|'s collection of FieldTrials.
bool IsFieldTrialPresent(const SystemProfileProto& proto,
                         const std::string& trial_name,
                         const std::string& group_name) {
  const variations::ActiveGroupId id =
      variations::MakeActiveGroupId(trial_name, group_name);

  for (const auto& trial : proto.field_trial()) {
    if (trial.name_id() == id.name && trial.group_id() == id.group) {
      return true;
    }
  }
  return false;
}

class TestMetricsService : public MetricsService {
 public:
  TestMetricsService(MetricsStateManager* state_manager,
                     MetricsServiceClient* client,
                     PrefService* local_state)
      : MetricsService(state_manager, client, local_state) {}

  TestMetricsService(const TestMetricsService&) = delete;
  TestMetricsService& operator=(const TestMetricsService&) = delete;

  ~TestMetricsService() override = default;

  using MetricsService::INIT_TASK_DONE;
  using MetricsService::INIT_TASK_SCHEDULED;
  using MetricsService::RecordCurrentEnvironmentHelper;
  using MetricsService::SENDING_LOGS;
  using MetricsService::state;

  // MetricsService:
  void SetPersistentSystemProfile(const std::string& serialized_proto,
                                  bool complete) override {
    persistent_system_profile_provided_ = true;
    persistent_system_profile_complete_ = complete;
  }

  bool persistent_system_profile_provided() const {
    return persistent_system_profile_provided_;
  }
  bool persistent_system_profile_complete() const {
    return persistent_system_profile_complete_;
  }

 private:
  bool persistent_system_profile_provided_ = false;
  bool persistent_system_profile_complete_ = false;
};

class TestMetricsLog : public MetricsLog {
 public:
  TestMetricsLog(const std::string& client_id,
                 int session_id,
                 MetricsServiceClient* client)
      : MetricsLog(client_id, session_id, MetricsLog::ONGOING_LOG, client) {}

  TestMetricsLog(const TestMetricsLog&) = delete;
  TestMetricsLog& operator=(const TestMetricsLog&) = delete;

  ~TestMetricsLog() override = default;
};

const char kOnDidCreateMetricsLogHistogramName[] = "Test.OnDidCreateMetricsLog";

class TestMetricsProviderForOnDidCreateMetricsLog : public TestMetricsProvider {
 public:
  TestMetricsProviderForOnDidCreateMetricsLog() = default;
  ~TestMetricsProviderForOnDidCreateMetricsLog() override = default;

  void OnDidCreateMetricsLog() override {
    base::UmaHistogramBoolean(kOnDidCreateMetricsLogHistogramName, true);
  }
};

const char kProvideHistogramsHistogramName[] = "Test.ProvideHistograms";

class TestMetricsProviderForProvideHistograms : public TestMetricsProvider {
 public:
  TestMetricsProviderForProvideHistograms() = default;
  ~TestMetricsProviderForProvideHistograms() override = default;

  bool ProvideHistograms() override {
    base::UmaHistogramBoolean(kProvideHistogramsHistogramName, true);
    return true;
  }

  void ProvideCurrentSessionData(
      ChromeUserMetricsExtension* uma_proto) override {
    MetricsProvider::ProvideCurrentSessionData(uma_proto);
  }
};

class TestMetricsProviderForProvideHistogramsEarlyReturn
    : public TestMetricsProviderForProvideHistograms {
 public:
  TestMetricsProviderForProvideHistogramsEarlyReturn() = default;
  ~TestMetricsProviderForProvideHistogramsEarlyReturn() override = default;

  void OnDidCreateMetricsLog() override {}
};

class TestIndependentMetricsProvider : public MetricsProvider {
 public:
  TestIndependentMetricsProvider() = default;
  ~TestIndependentMetricsProvider() override = default;

  // MetricsProvider:
  bool HasIndependentMetrics() override {
    // Only return true the first time this is called (i.e., we only have one
    // independent log to provide).
    if (!has_independent_metrics_called_) {
      has_independent_metrics_called_ = true;
      return true;
    }
    return false;
  }
  void ProvideIndependentMetrics(
      base::OnceClosure serialize_log_callback,
      base::OnceCallback<void(bool)> done_callback,
      ChromeUserMetricsExtension* uma_proto,
      base::HistogramSnapshotManager* snapshot_manager) override {
    provide_independent_metrics_called_ = true;
    uma_proto->set_client_id(123);
    std::move(done_callback).Run(true);
  }

  bool has_independent_metrics_called() const {
    return has_independent_metrics_called_;
  }

  bool provide_independent_metrics_called() const {
    return provide_independent_metrics_called_;
  }

 private:
  bool has_independent_metrics_called_ = false;
  bool provide_independent_metrics_called_ = false;
};

class MetricsServiceTest : public testing::Test {
 public:
  MetricsServiceTest()
      : enabled_state_provider_(new TestEnabledStateProvider(false, false)) {
    base::SetRecordActionTaskRunner(
        task_environment_.GetMainThreadTaskRunner());
    MetricsService::RegisterPrefs(testing_local_state_.registry());
  }

  MetricsServiceTest(const MetricsServiceTest&) = delete;
  MetricsServiceTest& operator=(const MetricsServiceTest&) = delete;

  ~MetricsServiceTest() override = default;

  void SetUp() override { ASSERT_TRUE(temp_dir_.CreateUniqueTempDir()); }

  MetricsStateManager* GetMetricsStateManager(
      const base::FilePath& user_data_dir = base::FilePath(),
      StartupVisibility startup_visibility = StartupVisibility::kUnknown) {
    // Lazy-initialize the metrics_state_manager so that it correctly reads the
    // stability state from prefs after tests have a chance to initialize it.
    if (!metrics_state_manager_) {
      metrics_state_manager_ = MetricsStateManager::Create(
          GetLocalState(), enabled_state_provider_.get(), std::wstring(),
          user_data_dir, startup_visibility);
      metrics_state_manager_->InstantiateFieldTrialList();
    }
    return metrics_state_manager_.get();
  }

  std::unique_ptr<TestUnsentLogStore> InitializeTestLogStoreAndGet() {
    TestUnsentLogStore::RegisterPrefs(testing_local_state_.registry());
    return std::make_unique<TestUnsentLogStore>(GetLocalState());
  }

  PrefService* GetLocalState() { return &testing_local_state_; }

  // Sets metrics reporting as enabled for testing.
  void EnableMetricsReporting() { SetMetricsReporting(true); }

  // Sets metrics reporting for testing.
  void SetMetricsReporting(bool enabled) {
    enabled_state_provider_->set_consent(enabled);
    enabled_state_provider_->set_enabled(enabled);
  }

  // Finds a histogram with the specified |name_hash| in |histograms|.
  const base::HistogramBase* FindHistogram(
      const base::StatisticsRecorder::Histograms& histograms,
      uint64_t name_hash) {
    for (const base::HistogramBase* histogram : histograms) {
      if (name_hash == base::HashMetricName(histogram->histogram_name())) {
        return histogram;
      }
    }
    return nullptr;
  }

  // Checks whether |uma_log| contains any histograms that are not flagged
  // with kUmaStabilityHistogramFlag. Stability logs should only contain such
  // histograms.
  void CheckForNonStabilityHistograms(
      const ChromeUserMetricsExtension& uma_log) {
    const int kStabilityFlags = base::HistogramBase::kUmaStabilityHistogramFlag;
    const base::StatisticsRecorder::Histograms histograms =
        base::StatisticsRecorder::GetHistograms();
    for (int i = 0; i < uma_log.histogram_event_size(); ++i) {
      const uint64_t hash = uma_log.histogram_event(i).name_hash();

      const base::HistogramBase* histogram = FindHistogram(histograms, hash);
      EXPECT_TRUE(histogram) << hash;

      EXPECT_TRUE(histogram->HasFlags(kStabilityFlags)) << hash;
    }
  }

  // Returns the number of samples logged to the specified histogram or 0 if
  // the histogram was not found.
  int GetHistogramSampleCount(const ChromeUserMetricsExtension& uma_log,
                              std::string_view histogram_name) {
    const auto histogram_name_hash = base::HashMetricName(histogram_name);
    int samples = 0;
    for (int i = 0; i < uma_log.histogram_event_size(); ++i) {
      const auto& histogram = uma_log.histogram_event(i);
      if (histogram.name_hash() == histogram_name_hash) {
        for (int j = 0; j < histogram.bucket_size(); ++j) {
          const auto& bucket = histogram.bucket(j);
          // Per proto comments, count field not being set means 1 sample.
          samples += (!bucket.has_count() ? 1 : bucket.count());
        }
      }
    }
    return samples;
  }

  // Returns the sampled count of the |kOnDidCreateMetricsLogHistogramName|
  // histogram in the currently staged log in |test_log_store|.
  int GetSampleCountOfOnDidCreateLogHistogram(MetricsLogStore* test_log_store) {
    ChromeUserMetricsExtension log;
    EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &log));
    return GetHistogramSampleCount(log, kOnDidCreateMetricsLogHistogramName);
  }

  int GetNumberOfUserActions(MetricsLogStore* test_log_store) {
    ChromeUserMetricsExtension log;
    EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &log));
    return log.user_action_event_size();
  }

#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_IOS)
  // Returns the value of `fg_bg_id` in the the currently staged log in
  // `test_log_store`.
  int GetFgBgId(MetricsLogStore* test_log_store) {
    ChromeUserMetricsExtension log;
    EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &log));
    EXPECT_TRUE(log.system_profile().has_fg_bg_id());
    return log.system_profile().fg_bg_id();
  }

  // Returns the sample count of the `kBeforeBackgroundHistogram` histogram in
  // the currently staged log in `test_log_store`.
  int GetSampleCountOfBeforeBackgroundHistogram(
      MetricsLogStore* test_log_store) {
    ChromeUserMetricsExtension log;
    EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &log));
    return GetHistogramSampleCount(log, kBeforeBackgroundHistogram);
  }

  // Returns the sample count of the `kBeforeForegroundHistogram` histogram in
  // the currently staged log in `test_log_store`.
  int GetSampleCountOfBeforeForegroundHistogram(
      MetricsLogStore* test_log_store) {
    ChromeUserMetricsExtension log;
    EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &log));
    return GetHistogramSampleCount(log, kBeforeForegroundHistogram);
  }
#endif  // BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_IOS)

  const base::FilePath user_data_dir_path() { return temp_dir_.GetPath(); }

 protected:
  base::test::TaskEnvironment task_environment_{
      base::test::TaskEnvironment::TimeSource::MOCK_TIME};

 private:
  std::unique_ptr<TestEnabledStateProvider> enabled_state_provider_;
  TestingPrefServiceSimple testing_local_state_;
  std::unique_ptr<MetricsStateManager> metrics_state_manager_;
  base::ScopedTempDir temp_dir_;
};

struct StartupVisibilityTestParams {
  metrics::StartupVisibility startup_visibility;
  bool expected_beacon_value;
};

class MetricsServiceTestWithStartupVisibility
    : public MetricsServiceTest,
      public ::testing::WithParamInterface<StartupVisibilityTestParams> {};

class ExperimentTestMetricsProvider : public TestMetricsProvider {
 public:
  explicit ExperimentTestMetricsProvider(
      base::FieldTrial* profile_metrics_trial,
      base::FieldTrial* session_data_trial)
      : profile_metrics_trial_(profile_metrics_trial),
        session_data_trial_(session_data_trial) {}

  ~ExperimentTestMetricsProvider() override = default;

  void ProvideSystemProfileMetrics(
      SystemProfileProto* system_profile_proto) override {
    TestMetricsProvider::ProvideSystemProfileMetrics(system_profile_proto);
    profile_metrics_trial_->Activate();
  }

  void ProvideCurrentSessionData(
      ChromeUserMetricsExtension* uma_proto) override {
    TestMetricsProvider::ProvideCurrentSessionData(uma_proto);
    session_data_trial_->Activate();
  }

 private:
  raw_ptr<base::FieldTrial> profile_metrics_trial_;
  raw_ptr<base::FieldTrial> session_data_trial_;
};

bool HistogramExists(std::string_view name) {
  return base::StatisticsRecorder::FindHistogram(name) != nullptr;
}

base::HistogramBase::Count32 GetHistogramDeltaTotalCount(
    std::string_view name) {
  return base::StatisticsRecorder::FindHistogram(name)
      ->SnapshotDelta()
      ->TotalCount();
}

}  // namespace

TEST_F(MetricsServiceTest, RecordId) {
  EnableMetricsReporting();
  GetMetricsStateManager(user_data_dir_path())->ForceClientIdCreation();

  // Set an initial value for the record-ids, to make them predictable.
  GetLocalState()->SetInteger(prefs::kMetricsLogRecordId, 1000);

  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(user_data_dir_path()),
                             &client, GetLocalState());

  auto log1 = service.CreateLogForTesting(MetricsLog::ONGOING_LOG);
  auto log2 = service.CreateLogForTesting(MetricsLog::INITIAL_STABILITY_LOG);
  auto log3 = service.CreateLogForTesting(MetricsLog::INDEPENDENT_LOG);

  EXPECT_EQ(1001, log1->uma_proto()->record_id());
  EXPECT_EQ(1002, log2->uma_proto()->record_id());
  EXPECT_EQ(1003, log3->uma_proto()->record_id());
}

TEST_F(MetricsServiceTest, InitialStabilityLogAfterCleanShutDown) {
  base::HistogramTester histogram_tester;
  EnableMetricsReporting();
  // Write a beacon file indicating that Chrome exited cleanly. Note that the
  // crash streak value is arbitrary.
  const base::FilePath beacon_file_path =
      user_data_dir_path().Append(kCleanExitBeaconFilename);
  ASSERT_TRUE(base::WriteFile(
      beacon_file_path, CleanExitBeacon::CreateBeaconFileContentsForTesting(
                            /*exited_cleanly=*/true, /*crash_streak=*/1)));

  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(user_data_dir_path()),
                             &client, GetLocalState());

  TestMetricsProvider* test_provider = new TestMetricsProvider();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();

  // No initial stability log should be generated.
  EXPECT_FALSE(service.has_unsent_logs());

  // Ensure that HasPreviousSessionData() is always called on providers,
  // for consistency, even if other conditions already indicate their presence.
  EXPECT_TRUE(test_provider->has_initial_stability_metrics_called());

  // The test provider should not have been called upon to provide initial
  // stability nor regular stability metrics.
  EXPECT_FALSE(test_provider->provide_initial_stability_metrics_called());
  EXPECT_FALSE(test_provider->provide_stability_metrics_called());

  // As there wasn't an unclean shutdown, no browser crash samples should have
  // been emitted.
  histogram_tester.ExpectBucketCount("Stability.Counts2",
                                     StabilityEventType::kBrowserCrash, 0);
}

TEST_F(MetricsServiceTest, InitialStabilityLogAtProviderRequest) {
  base::HistogramTester histogram_tester;
  EnableMetricsReporting();

  // Save an existing system profile to prefs, to correspond to what would be
  // saved from a previous session.
  TestMetricsServiceClient client;
  TestMetricsLog log("0a94430b-18e5-43c8-a657-580f7e855ce1", 1, &client);
  // Manually override the log's session hash to something else to verify that
  // stability logs created later on using this environment will contain that
  // session hash.
  uint64_t modified_session_hash =
      log.uma_proto()->system_profile().session_hash() + 1;
  log.uma_proto()->mutable_system_profile()->set_session_hash(
      modified_session_hash);
  DelegatingProvider delegating_provider;
  TestMetricsService::RecordCurrentEnvironmentHelper(&log, GetLocalState(),
                                                     &delegating_provider);

  // Record stability build time and version from previous session, so that
  // stability metrics (including exited cleanly flag) won't be cleared.
  EnvironmentRecorder(GetLocalState())
      .SetBuildtimeAndVersion(MetricsLog::GetBuildTime(),
                              client.GetVersionString());

  // Write a beacon file indicating that Chrome exited cleanly. Note that the
  // crash streak value is arbitrary.
  const base::FilePath beacon_file_path =
      user_data_dir_path().Append(kCleanExitBeaconFilename);
  ASSERT_TRUE(base::WriteFile(
      beacon_file_path, CleanExitBeacon::CreateBeaconFileContentsForTesting(
                            /*exited_cleanly=*/true, /*crash_streak=*/1)));

  TestMetricsService service(GetMetricsStateManager(user_data_dir_path()),
                             &client, GetLocalState());
  // Add a metrics provider that requests a stability log.
  TestMetricsProvider* test_provider = new TestMetricsProvider();
  test_provider->set_has_initial_stability_metrics(true);
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();

  // The initial stability log should be generated and persisted in unsent logs.
  MetricsLogStore* test_log_store = service.LogStoreForTest();
  EXPECT_TRUE(test_log_store->has_unsent_logs());
  EXPECT_FALSE(test_log_store->has_staged_log());

  // Ensure that HasPreviousSessionData() is always called on providers,
  // for consistency, even if other conditions already indicate their presence.
  EXPECT_TRUE(test_provider->has_initial_stability_metrics_called());

  // The test provider should have been called upon to provide initial
  // stability and regular stability metrics.
  EXPECT_TRUE(test_provider->provide_initial_stability_metrics_called());
  EXPECT_TRUE(test_provider->provide_stability_metrics_called());

  // Stage the log and retrieve it.
  test_log_store->StageNextLog();
  EXPECT_TRUE(test_log_store->has_staged_log());

  ChromeUserMetricsExtension uma_log;
  EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &uma_log));

  EXPECT_TRUE(uma_log.has_client_id());
  EXPECT_TRUE(uma_log.has_session_id());
  EXPECT_TRUE(uma_log.has_system_profile());
  EXPECT_TRUE(uma_log.system_profile().has_session_hash());
  EXPECT_EQ(modified_session_hash, uma_log.system_profile().session_hash());
  EXPECT_EQ(0, uma_log.user_action_event_size());
  EXPECT_EQ(0, uma_log.omnibox_event_size());
  CheckForNonStabilityHistograms(uma_log);
  EXPECT_EQ(
      1, GetHistogramSampleCount(uma_log, "UMA.InitialStabilityRecordBeacon"));

  // As there wasn't an unclean shutdown, no browser crash samples should have
  // been emitted.
  histogram_tester.ExpectBucketCount("Stability.Counts2",
                                     StabilityEventType::kBrowserCrash, 0);
}

TEST_F(MetricsServiceTest, IndependentLogAtProviderRequest) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  // Create a a provider that will have one independent log to provide.
  auto* test_provider = new TestIndependentMetricsProvider();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Verify that the independent log provider has not yet been called, and emit
  // a histogram. This histogram should not be put into the independent log.
  EXPECT_FALSE(test_provider->has_independent_metrics_called());
  EXPECT_FALSE(test_provider->provide_independent_metrics_called());
  const std::string test_histogram = "Test.Histogram";
  base::UmaHistogramBoolean(test_histogram, true);

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time by another |initialization_delay|, which is when
  // metrics providers are called to provide independent logs.
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_TRUE(test_provider->has_independent_metrics_called());
  EXPECT_TRUE(test_provider->provide_independent_metrics_called());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| twice, we only need to fast forward by
  // N - 2 * |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      2 * initialization_delay);
  EXPECT_EQ(TestMetricsService::SENDING_LOGS, service.state());

  MetricsLogStore* test_log_store = service.LogStoreForTest();

  // The currently staged log should be the independent log created by the
  // independent log provider. The log should have a client id of 123. It should
  // also not contain |test_histogram|.
  ASSERT_TRUE(test_log_store->has_staged_log());
  ChromeUserMetricsExtension uma_log;
  EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &uma_log));
  EXPECT_EQ(uma_log.client_id(), 123UL);
  EXPECT_EQ(GetHistogramSampleCount(uma_log, test_histogram), 0);

  // Discard the staged log and stage the next one. It should be the first
  // ongoing log.
  test_log_store->DiscardStagedLog();
  ASSERT_TRUE(test_log_store->has_unsent_logs());
  test_log_store->StageNextLog();
  ASSERT_TRUE(test_log_store->has_staged_log());

  // Verify that the first ongoing log contains |test_histogram| (it should not
  // have been put into the independent log).
  EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &uma_log));
  EXPECT_EQ(GetHistogramSampleCount(uma_log, test_histogram), 1);
}

TEST_F(MetricsServiceTest, OnDidCreateMetricsLogAtShutdown) {
  base::HistogramTester histogram_tester;
  EnableMetricsReporting();
  TestMetricsServiceClient client;

  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  // Create a provider that will log to |kOnDidCreateMetricsLogHistogramName|
  // in OnDidCreateMetricsLog().
  auto* test_provider = new TestMetricsProviderForOnDidCreateMetricsLog();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();

  // OnDidCreateMetricsLog() is called once when the first ongoing log is
  // created.
  histogram_tester.ExpectBucketCount(kOnDidCreateMetricsLogHistogramName, true,
                                     1);
  service.Stop();

  // OnDidCreateMetricsLog() will be called during shutdown to emit histograms.
  histogram_tester.ExpectBucketCount(kOnDidCreateMetricsLogHistogramName, true,
                                     2);

  // Clean up histograms.
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kOnDidCreateMetricsLogHistogramName);
}

TEST_F(MetricsServiceTest, ProvideHistograms) {
  base::HistogramTester histogram_tester;
  EnableMetricsReporting();
  TestMetricsServiceClient client;

  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  // Create a provider that will log to |kProvideHistogramsHistogramName|
  // in ProvideHistograms().
  auto* test_provider = new TestMetricsProviderForProvideHistograms();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();

  // ProvideHistograms() is called in OnDidCreateMetricsLog().
  histogram_tester.ExpectBucketCount(kProvideHistogramsHistogramName, true, 1);

  service.StageCurrentLogForTest();

  histogram_tester.ExpectBucketCount(kProvideHistogramsHistogramName, true, 2);

  service.Stop();

  // Clean up histograms.
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kProvideHistogramsHistogramName);
}

TEST_F(MetricsServiceTest, ProvideHistogramsEarlyReturn) {
  base::HistogramTester histogram_tester;
  EnableMetricsReporting();
  TestMetricsServiceClient client;

  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  // Create a provider that will log to |kOnDidCreateMetricsLogHistogramName|
  // in OnDidCreateMetricsLog().
  auto* test_provider =
      new TestMetricsProviderForProvideHistogramsEarlyReturn();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();

  // Make sure no histogram is emitted when having an early return.
  histogram_tester.ExpectBucketCount(kProvideHistogramsHistogramName, true, 0);

  service.StageCurrentLogForTest();
  // ProvideHistograms() should be called in ProvideCurrentSessionData() if
  // histograms haven't been emitted.
  histogram_tester.ExpectBucketCount(kProvideHistogramsHistogramName, true, 1);

  // Try another log to make sure emission status is reset between logs.
  service.LogStoreForTest()->DiscardStagedLog();
  service.StageCurrentLogForTest();
  histogram_tester.ExpectBucketCount(kProvideHistogramsHistogramName, true, 2);

  service.Stop();

  // Clean up histograms.
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kProvideHistogramsHistogramName);
}

#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_IOS)
// Verifies that logs contain a proper `fg_bg_id`, which changes upon
// backgrounding or foregrounding.
TEST_F(MetricsServiceTest, FgBgId) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Immediately send a foreground notification to simulate the application
  // being launched. This should not close the current log (since it is too
  // early to do so), and it should not cause it to have its `fg_bg_id` cleared
  // (verified below by the first "ongoing log").
  service.OnAppEnterForeground(/*force_open_new_log=*/true);
  MetricsLogStore* test_log_store = service.LogStoreForTest();
  EXPECT_FALSE(test_log_store->has_unsent_logs());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()));
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());

  // Stage the next log, which should be the first ongoing log. Check that the
  // log has a `fg_bg_id` value set, and remember it to compare with follow up
  // logs.
  test_log_store->StageNextLog();
  int fg_bg_id1 = GetFgBgId(test_log_store);

  // Send another foreground notification, which will create a second "ongoing
  // log". Since we are already foregrounded (see above), this should not result
  // in a new `fg_bg_id` (verified by the third "ongoing log" below). These
  // duplicate notifications can often happen on platforms like iOS.
  test_log_store->DiscardStagedLog();
  service.OnAppEnterForeground(/*force_open_new_log=*/true);
  test_log_store->StageNextLog();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id1);

  // Close and stage the next log, which is the third "ongoing log". Check that
  // it has the same `fg_bg_id` as the last two logs.
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id1);

  // Simulate backgrounding. The act of backgrounding will create a fourth
  // "ongoing log" -- which should contain the last metrics from when the
  // browser was in the foreground, and hence should have the same `fg_bg_id`
  // as the previous two logs.
  test_log_store->DiscardStagedLog();
  base::UmaHistogramBoolean(kBeforeBackgroundHistogram, true);
  service.OnAppEnterBackground(/*keep_recording_in_background=*/true);
  test_log_store->StageNextLog();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id1);
  EXPECT_EQ(GetSampleCountOfBeforeBackgroundHistogram(test_log_store), 1);

  // Create a fifth then sixth "ongoing log". These logs should only contain
  // metrics from after the browser was backgrounded, and hence have the same
  // `fg_bg_id`, but it should be different than all the previous logs.
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  int fg_bg_id2 = GetFgBgId(test_log_store);
  EXPECT_NE(fg_bg_id2, fg_bg_id1);
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id2);

  // Simulate foregrounding. The act of foregrounding will create a seventh
  // "ongoing log" -- which should contain the last metrics from when the
  // browser was in the background, and hence should have the same `fg_bg_id`
  // as the previous two logs.
  test_log_store->DiscardStagedLog();
  base::UmaHistogramBoolean(kBeforeForegroundHistogram, true);
  service.OnAppEnterForeground(/*force_open_new_log=*/true);
  test_log_store->StageNextLog();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id2);
  EXPECT_EQ(GetSampleCountOfBeforeForegroundHistogram(test_log_store), 1);

  // Lastly, for good measure, create an eight then ninth "ongoing log". These
  // logs should only contain metrics from after the browser was foregrounded,
  // and hence have the same `fg_bg_id`, but it should be different than all the
  // previous logs.
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  int fg_bg_id3 = GetFgBgId(test_log_store);
  EXPECT_NE(fg_bg_id3, fg_bg_id2);
  EXPECT_NE(fg_bg_id3, fg_bg_id1);
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id3);

  // End test and clean up histograms.
  service.Stop();
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kBeforeBackgroundHistogram);
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kBeforeForegroundHistogram);
}

// Verifies that if backgrounding and/or foregrounding happens too early, the
// first log will contain metrics from both background and foreground periods,
// in which case its `fg_bg_id` should be unset.
TEST_F(MetricsServiceTest, FgBgId_BackgroundForegroundBeforeFirstLog) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());
  MetricsLogStore* test_log_store = service.LogStoreForTest();

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Immediately send a foreground notification to simulate the application
  // being launched. This should not close the current log (since it is too
  // early to do so), and it should not cause it to have its `fg_bg_id` cleared
  // (verified below).
  service.OnAppEnterForeground(/*force_open_new_log=*/true);
  EXPECT_FALSE(test_log_store->has_unsent_logs());

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // At this stage, the first log has not been closed yet. Perform background
  // and foreground actions. Since it is too early, these actions should not
  // close a log.
  base::UmaHistogramBoolean(kBeforeBackgroundHistogram, true);
  service.OnAppEnterBackground(/*keep_recording_in_background=*/true);
  base::UmaHistogramBoolean(kBeforeForegroundHistogram, true);
  service.OnAppEnterForeground(/*force_open_new_log=*/true);
  ASSERT_FALSE(test_log_store->has_unsent_logs());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());
  test_log_store->StageNextLog();

  // The log should contain both histograms, despite being emitted in different
  // background/foreground "periods". For that same reason, the log should not
  // have a `fg_bg_id`.
  EXPECT_EQ(GetSampleCountOfBeforeBackgroundHistogram(test_log_store), 1);
  EXPECT_EQ(GetSampleCountOfBeforeForegroundHistogram(test_log_store), 1);
  ChromeUserMetricsExtension log;
  EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &log));
  EXPECT_FALSE(log.system_profile().has_fg_bg_id());

  // Logs created after this should have `fg_bg_id` set like usual. Create a
  // second then third "ongoing log" to verify this. These logs should contain
  // metrics from the same foreground "period", and hence have the same
  // `fg_bg_id`.
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  int fg_bg_id = GetFgBgId(test_log_store);
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id);

  // End test and clean up histograms.
  service.Stop();
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kBeforeBackgroundHistogram);
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kBeforeForegroundHistogram);
}

// Certain platforms (iOS, WebView) do not record while in the background, and
// do not close a log when foregrounding. In those cases, logs may contain data
// that were emitted while the browser was in the background and foreground.
// This test verifies that in those scenarios, `fg_bg_id` is unset.
TEST_F(MetricsServiceTest, FgBgId_NoRecordingInBackground) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Immediately send a foreground notification to simulate the application
  // being launched. This should not close the current log (since it is too
  // early to do so, and `force_open_new_log` is set to false), and it should
  // not cause it to have its `fg_bg_id` cleared (verified below).
  service.OnAppEnterForeground(/*force_open_new_log=*/false);
  MetricsLogStore* test_log_store = service.LogStoreForTest();
  EXPECT_FALSE(test_log_store->has_unsent_logs());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()));
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());

  // Stage the next log, which should be the first ongoing log. Check that the
  // log has a `fg_bg_id` value set, and remember it to compare with follow up
  // logs.
  test_log_store->StageNextLog();
  int fg_bg_id1 = GetFgBgId(test_log_store);

  // Send another foreground notification. Since we are already foregrounded
  // (see above), this should not result in a new `fg_bg_id` (verified by the
  // second "ongoing log" below). These duplicate notifications can often happen
  // on platforms like iOS.
  test_log_store->DiscardStagedLog();
  service.OnAppEnterForeground(/*force_open_new_log=*/false);
  EXPECT_FALSE(test_log_store->has_unsent_logs());

  // Simulate backgrounding. The act of backgrounding will create a second
  // "ongoing log" -- which should contain the last metrics from when the
  // browser was in the foreground, and hence should have the same `fg_bg_id`
  // as the previous log.
  base::UmaHistogramBoolean(kBeforeBackgroundHistogram, true);
  service.OnAppEnterBackground(/*keep_recording_in_background=*/false);
  test_log_store->StageNextLog();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id1);
  EXPECT_EQ(GetSampleCountOfBeforeBackgroundHistogram(test_log_store), 1);
  test_log_store->DiscardStagedLog();

  // Because `keep_recording_in_background` was set to false, logs will not be
  // periodically be created/closed while in the background.

  // Simulate foregrounding. Because `force_open_new_log` is set to false, the
  // act of foregrounding will not create an "ongoing log".
  EXPECT_FALSE(test_log_store->has_unsent_logs());
  base::UmaHistogramBoolean(kBeforeForegroundHistogram, true);
  service.OnAppEnterForeground(/*force_open_new_log=*/false);
  EXPECT_FALSE(test_log_store->has_unsent_logs());

  // Now that the browser is in the foreground, logs will start periodically
  // being created/closed again. However, the next one may contain metrics from
  // before and after the foreground, and so should not have a `fg_bg_id` value
  // set.
  service.StageCurrentLogForTest();
  EXPECT_EQ(GetSampleCountOfBeforeForegroundHistogram(test_log_store), 1);
  ChromeUserMetricsExtension log;
  EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &log));
  EXPECT_FALSE(log.system_profile().has_fg_bg_id());

  // For good measure, verify that the logs created after this have a proper
  // `fg_bg_id` value set, but it should be different than the first one.
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  int fg_bg_id2 = GetFgBgId(test_log_store);
  EXPECT_NE(fg_bg_id2, fg_bg_id1);
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(GetFgBgId(test_log_store), fg_bg_id2);

  // End test and clean up histograms.
  service.Stop();
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kBeforeBackgroundHistogram);
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kBeforeForegroundHistogram);
}
#endif  // BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_IOS)

INSTANTIATE_TEST_SUITE_P(
    All,
    MetricsServiceTestWithStartupVisibility,
    ::testing::Values(
        StartupVisibilityTestParams{
            .startup_visibility = StartupVisibility::kUnknown,
            .expected_beacon_value = true},
        StartupVisibilityTestParams{
            .startup_visibility = StartupVisibility::kBackground,
            .expected_beacon_value = true},
        StartupVisibilityTestParams{
            .startup_visibility = StartupVisibility::kForeground,
            .expected_beacon_value = false}));

TEST_P(MetricsServiceTestWithStartupVisibility, InitialStabilityLogAfterCrash) {
  base::HistogramTester histogram_tester;
  PrefService* local_state = GetLocalState();
  EnableMetricsReporting();

  // Write a beacon file indicating that Chrome exited uncleanly. Note that the
  // crash streak value is arbitrary.
  const base::FilePath beacon_file_path =
      user_data_dir_path().Append(kCleanExitBeaconFilename);
  ASSERT_TRUE(base::WriteFile(
      beacon_file_path, CleanExitBeacon::CreateBeaconFileContentsForTesting(
                            /*exited_cleanly=*/false, /*crash_streak=*/1)));

  // Set up prefs to simulate restarting after a crash.

  // Save an existing system profile to prefs, to correspond to what would be
  // saved from a previous session.
  TestMetricsServiceClient client;
  const std::string kCrashedVersion = "4.0.321.0-64-devel";
  client.set_version_string(kCrashedVersion);
  TestMetricsLog log("0a94430b-18e5-43c8-a657-580f7e855ce1", 1, &client);
  DelegatingProvider delegating_provider;
  TestMetricsService::RecordCurrentEnvironmentHelper(&log, local_state,
                                                     &delegating_provider);

  // Record stability build time and version from previous session, so that
  // stability metrics (including exited cleanly flag) won't be cleared.
  EnvironmentRecorder(local_state)
      .SetBuildtimeAndVersion(MetricsLog::GetBuildTime(),
                              client.GetVersionString());

  const std::string kCurrentVersion = "5.0.322.0-64-devel";
  client.set_version_string(kCurrentVersion);

  StartupVisibilityTestParams params = GetParam();
  TestMetricsService service(
      GetMetricsStateManager(user_data_dir_path(), params.startup_visibility),
      &client, local_state);
  // Add a provider.
  TestMetricsProvider* test_provider = new TestMetricsProvider();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));
  service.InitializeMetricsRecordingState();

  // Verify that Chrome is (or is not) watching for crashes by checking the
  // beacon value.
  std::string beacon_file_contents;
  ASSERT_TRUE(base::ReadFileToString(beacon_file_path, &beacon_file_contents));
  std::string partial_expected_contents;
#if BUILDFLAG(IS_ANDROID)
  // Whether Chrome is watching for crashes after
  // InitializeMetricsRecordingState() depends on the type of Android Chrome
  // session. See the comments in MetricsService::InitializeMetricsState() for
  // more details.
  const std::string beacon_value = base::ToString(params.expected_beacon_value);
  partial_expected_contents = "exited_cleanly\":" + beacon_value;
#else
  partial_expected_contents = "exited_cleanly\":false";
#endif  // BUILDFLAG(IS_ANDROID)
  EXPECT_TRUE(beacon_file_contents.contains(partial_expected_contents));

  // The initial stability log should be generated and persisted in unsent logs.
  MetricsLogStore* test_log_store = service.LogStoreForTest();
  EXPECT_TRUE(test_log_store->has_unsent_logs());
  EXPECT_FALSE(test_log_store->has_staged_log());

  // Ensure that HasPreviousSessionData() is always called on providers,
  // for consistency, even if other conditions already indicate their presence.
  EXPECT_TRUE(test_provider->has_initial_stability_metrics_called());

  // The test provider should have been called upon to provide initial
  // stability and regular stability metrics.
  EXPECT_TRUE(test_provider->provide_initial_stability_metrics_called());
  EXPECT_TRUE(test_provider->provide_stability_metrics_called());

  // The test provider should have been called when the initial stability log
  // was closed.
  EXPECT_TRUE(test_provider->record_initial_histogram_snapshots_called());

  // Stage the log and retrieve it.
  test_log_store->StageNextLog();
  EXPECT_TRUE(test_log_store->has_staged_log());

  ChromeUserMetricsExtension uma_log;
  EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &uma_log));

  EXPECT_TRUE(uma_log.has_client_id());
  EXPECT_TRUE(uma_log.has_session_id());
  EXPECT_TRUE(uma_log.has_system_profile());
  EXPECT_EQ(0, uma_log.user_action_event_size());
  EXPECT_EQ(0, uma_log.omnibox_event_size());
  CheckForNonStabilityHistograms(uma_log);
  EXPECT_EQ(
      1, GetHistogramSampleCount(uma_log, "UMA.InitialStabilityRecordBeacon"));

  // Verify that the histograms emitted by the test provider made it into the
  // log.
  EXPECT_EQ(GetHistogramSampleCount(uma_log, "TestMetricsProvider.Initial"), 1);
  EXPECT_EQ(GetHistogramSampleCount(uma_log, "TestMetricsProvider.Regular"), 1);

  EXPECT_EQ(kCrashedVersion, uma_log.system_profile().app_version());
  EXPECT_EQ(kCurrentVersion,
            uma_log.system_profile().log_written_by_app_version());

  histogram_tester.ExpectBucketCount("Stability.Counts2",
                                     StabilityEventType::kBrowserCrash, 1);
}

TEST_F(MetricsServiceTest, InitialLogsHaveOnDidCreateMetricsLogHistograms) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  // Create a provider that will log to |kOnDidCreateMetricsLogHistogramName|
  // in OnDidCreateMetricsLog()
  auto* test_provider = new TestMetricsProviderForOnDidCreateMetricsLog();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log. Also verify that the test provider
  // was called when closing the log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());
  EXPECT_TRUE(test_provider->record_histogram_snapshots_called());

  MetricsLogStore* test_log_store = service.LogStoreForTest();

  // Stage the next log, which should be the first ongoing log.
  // Check that it has one sample in |kOnDidCreateMetricsLogHistogramName|.
  test_log_store->StageNextLog();
  EXPECT_EQ(1, GetSampleCountOfOnDidCreateLogHistogram(test_log_store));

  // Discard the staged log and close and stage the next log, which is the
  // second "ongoing log".
  // Check that it has one sample in |kOnDidCreateMetricsLogHistogramName|.
  // Also verify that the test provider was called when closing the new log.
  test_provider->set_record_histogram_snapshots_called(false);
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(1, GetSampleCountOfOnDidCreateLogHistogram(test_log_store));
  EXPECT_TRUE(test_provider->record_histogram_snapshots_called());

  // Check one more log for good measure.
  test_provider->set_record_histogram_snapshots_called(false);
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(1, GetSampleCountOfOnDidCreateLogHistogram(test_log_store));
  EXPECT_TRUE(test_provider->record_histogram_snapshots_called());

  service.Stop();

  // Clean up histograms.
  base::StatisticsRecorder::ForgetHistogramForTesting(
      kOnDidCreateMetricsLogHistogramName);
}

TEST_F(MetricsServiceTest, MarkCurrentHistogramsAsReported) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  // Emit to histogram |Test.Before.Histogram|.
  ASSERT_FALSE(HistogramExists("Test.Before.Histogram"));
  base::UmaHistogramBoolean("Test.Before.Histogram", true);
  ASSERT_TRUE(HistogramExists("Test.Before.Histogram"));

  // Mark histogram data that has been collected until now (in particular, the
  // |Test.Before.Histogram| sample) as reported.
  service.MarkCurrentHistogramsAsReported();

  // Emit to histogram |Test.After.Histogram|.
  ASSERT_FALSE(HistogramExists("Test.After.Histogram"));
  base::UmaHistogramBoolean("Test.After.Histogram", true);
  ASSERT_TRUE(HistogramExists("Test.After.Histogram"));

  // Verify that the |Test.Before.Histogram| sample was marked as reported, and
  // is not included in the next snapshot.
  EXPECT_EQ(0, GetHistogramDeltaTotalCount("Test.Before.Histogram"));
  // Verify that the |Test.After.Histogram| sample was not marked as reported,
  // and is included in the next snapshot.
  EXPECT_EQ(1, GetHistogramDeltaTotalCount("Test.After.Histogram"));

  // Clean up histograms.
  base::StatisticsRecorder::ForgetHistogramForTesting("Test.Before.Histogram");
  base::StatisticsRecorder::ForgetHistogramForTesting("Test.After.Histogram");
}

TEST_F(MetricsServiceTest, LogHasUserActions) {
  // This test verifies that user actions are properly captured in UMA logs.
  // In particular, it checks that the first log has actions, a behavior that
  // was buggy in the past, plus additional checks for subsequent logs with
  // different numbers of actions.
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();

  // Start() will create an initial log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  base::RecordAction(base::UserMetricsAction("TestAction"));
  base::RecordAction(base::UserMetricsAction("TestAction"));
  base::RecordAction(base::UserMetricsAction("DifferentAction"));

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());

  MetricsLogStore* test_log_store = service.LogStoreForTest();

  // Stage the next log, which should be the initial metrics log.
  test_log_store->StageNextLog();
  EXPECT_EQ(3, GetNumberOfUserActions(test_log_store));

  // Log another action.
  base::RecordAction(base::UserMetricsAction("TestAction"));
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(1, GetNumberOfUserActions(test_log_store));

  // Check a log with no actions.
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(0, GetNumberOfUserActions(test_log_store));

  // And another one with a couple.
  base::RecordAction(base::UserMetricsAction("TestAction"));
  base::RecordAction(base::UserMetricsAction("TestAction"));
  test_log_store->DiscardStagedLog();
  service.StageCurrentLogForTest();
  EXPECT_EQ(2, GetNumberOfUserActions(test_log_store));
}

TEST_F(MetricsServiceTest, FirstLogCreatedBeforeUnsentLogsSent) {
  // This test checks that we will create and serialize the first ongoing log
  // before starting to send unsent logs from the past session. The latter is
  // simulated by injecting some fake ongoing logs into the MetricsLogStore.
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  MetricsLogStore* test_log_store = service.LogStoreForTest();

  // Set up the log store with an existing fake log entry. The string content
  // is never deserialized to proto, so we're just passing some dummy content.
  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(0u, test_log_store->ongoing_log_count());
  test_log_store->StoreLog("blah_blah", MetricsLog::ONGOING_LOG, LogMetadata(),
                           MetricsLogsEventManager::CreateReason::kUnknown);
  // Note: |initial_log_count()| refers to initial stability logs, so the above
  // log is counted an ongoing log (per its type).
  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(1u, test_log_store->ongoing_log_count());

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());
  // When the init task is complete, the first ongoing log should be created
  // and added to the ongoing logs.
  EXPECT_EQ(0u, test_log_store->initial_log_count());
  EXPECT_EQ(2u, test_log_store->ongoing_log_count());
}

// Verify that calling StartOutOfBandUploadIfPossible() triggers an upload when
// called after the initial ongoing logs have been uploaded.
TEST_F(MetricsServiceTest, OutOfBandLogUpload) {
  // Initial set-up.
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());
  service.InitializeMetricsRecordingState();
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Fast forward the time by `initialization_delay`, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());

  // Fast forward the time so that the upload loop starts uploading logs.
  base::TimeDelta unsent_log_interval =
      MetricsUploadScheduler::GetUnsentLogsInterval();
  task_environment_.FastForwardBy(unsent_log_interval);
  EXPECT_TRUE(client.uploader()->is_uploading());
  client.uploader()->CompleteUpload(200);

  // Assert that the uploader is no longer uploading, and then trigger an
  // upload.
  EXPECT_FALSE(client.uploader()->is_uploading());
  service.StartOutOfBandUploadIfPossible(
      MetricsService::OutOfBandUploadPasskey());

  // Fast forward the time so that the upload loop starts uploading logs.
  task_environment_.FastForwardBy(unsent_log_interval);
  EXPECT_TRUE(client.uploader()->is_uploading());
  client.uploader()->CompleteUpload(200);
}

TEST_F(MetricsServiceTest,
       MetricsProviderOnRecordingDisabledCalledOnInitialStop) {
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  TestMetricsProvider* test_provider = new TestMetricsProvider();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();
  service.Stop();

  EXPECT_TRUE(test_provider->on_recording_disabled_called());
}

TEST_F(MetricsServiceTest, MetricsProvidersInitialized) {
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  TestMetricsProvider* test_provider = new TestMetricsProvider();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();

  EXPECT_TRUE(test_provider->init_called());
}

// Verify that FieldTrials activated by a MetricsProvider are reported by the
// FieldTrialsProvider.
TEST_F(MetricsServiceTest, ActiveFieldTrialsReported) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  // Set up FieldTrials.
  const std::string trial_name1 = "CoffeeExperiment";
  const std::string group_name1 = "Free";
  base::FieldTrial* trial1 =
      base::FieldTrialList::CreateFieldTrial(trial_name1, group_name1);

  const std::string trial_name2 = "DonutExperiment";
  const std::string group_name2 = "MapleBacon";
  base::FieldTrial* trial2 =
      base::FieldTrialList::CreateFieldTrial(trial_name2, group_name2);

  service.RegisterMetricsProvider(
      std::make_unique<ExperimentTestMetricsProvider>(trial1, trial2));

  service.InitializeMetricsRecordingState();
  service.Start();
  service.StageCurrentLogForTest();

  MetricsLogStore* test_log_store = service.LogStoreForTest();
  ChromeUserMetricsExtension uma_log;
  EXPECT_TRUE(DecodeLogDataToProto(test_log_store->staged_log(), &uma_log));

  // Verify that the reported FieldTrial IDs are for the trial set up by this
  // test.
  EXPECT_TRUE(
      IsFieldTrialPresent(uma_log.system_profile(), trial_name1, group_name1));
  EXPECT_TRUE(
      IsFieldTrialPresent(uma_log.system_profile(), trial_name2, group_name2));
}

TEST_F(MetricsServiceTest, SystemProfileDataProvidedOnEnableRecording) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  TestMetricsProvider* test_provider = new TestMetricsProvider();
  service.RegisterMetricsProvider(
      std::unique_ptr<MetricsProvider>(test_provider));

  service.InitializeMetricsRecordingState();

  // ProvideSystemProfileMetrics() shouldn't be called initially.
  EXPECT_FALSE(test_provider->provide_system_profile_metrics_called());
  EXPECT_FALSE(service.persistent_system_profile_provided());

  service.Start();

  // Start should call ProvideSystemProfileMetrics().
  EXPECT_TRUE(test_provider->provide_system_profile_metrics_called());
  EXPECT_TRUE(service.persistent_system_profile_provided());
  EXPECT_FALSE(service.persistent_system_profile_complete());
}

// Verify that the two separate MetricsSchedulers (MetricsRotationScheduler and
// MetricsUploadScheduler) function together properly.
TEST_F(MetricsServiceTest, SplitRotation) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());
  service.InitializeMetricsRecordingState();
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log. The independent-metrics upload job
  // will be started and always be a task. This should also mark the rotation
  // scheduler as idle, so that the next time we attempt to create a log, we
  // return early (and don't create a log).
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  MetricsLogStore* log_store = service.LogStoreForTest();
  EXPECT_FALSE(log_store->has_unsent_logs());
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());
  EXPECT_TRUE(log_store->has_unsent_logs());
  EXPECT_EQ(1U, log_store->ongoing_log_count());

  // There should be three (delayed) tasks: one for querying independent logs
  // from metrics providers, one for uploading the unsent log, and one for
  // creating the next log.
  EXPECT_EQ(3U, task_environment_.GetPendingMainThreadTaskCount());

  // Fast forward the time so that the upload loop starts uploading logs.
  base::TimeDelta unsent_log_interval =
      MetricsUploadScheduler::GetUnsentLogsInterval();
  task_environment_.FastForwardBy(unsent_log_interval);
  EXPECT_TRUE(client.uploader()->is_uploading());
  // There should be two (delayed) tasks: one for querying independent logs from
  // metrics providers, and one for creating the next log. I.e., the task to
  // upload a log should be running, and should not be in the task queue
  // anymore. The uploading of this log will only be completed later on in order
  // to simulate an edge case here.
  EXPECT_EQ(2U, task_environment_.GetPendingMainThreadTaskCount());

  // Fast forward the time so that the task to create another log is run. This
  // time, however, it should return early due to being idle (i.e., not create a
  // log), and it should not post another task to create another log. I.e.,
  // there should only be one (delayed) task: one for querying independent logs
  // from metrics providers.
  // Note: The log is only created after |rotation_scheduler_interval| seconds,
  // and since we already fast forwarded by |unsent_log_interval| once, we only
  // need to fast forward by
  // |rotation_scheduler_interval| - |unsent_log_interval|.
  base::TimeDelta rotation_scheduler_interval = client.GetUploadInterval();
  task_environment_.FastForwardBy(rotation_scheduler_interval -
                                  unsent_log_interval);
  EXPECT_EQ(1U, log_store->ongoing_log_count());
  EXPECT_EQ(1U, task_environment_.GetPendingMainThreadTaskCount());

  // Simulate completing the upload. Since there is no other log to be uploaded,
  // no task should be re-posted. I.e., there should only be one (delayed)
  // task: one for querying independent logs from metrics providers.
  client.uploader()->CompleteUpload(200);
  EXPECT_FALSE(client.uploader()->is_uploading());
  EXPECT_FALSE(log_store->has_unsent_logs());
  EXPECT_EQ(1U, task_environment_.GetPendingMainThreadTaskCount());

  // Simulate interacting with the browser, which should 1) set the rotation
  // scheduler to not idle, 2) queue a task to upload the next log (if there is
  // one), and 3) queue a task to create the next log. I.e., there should be
  // three (delayed) tasks: one for querying independent logs from metrics
  // providers, one for uploading an unsent log, and one for creating the next
  // log.
  service.OnApplicationNotIdle();
  EXPECT_EQ(3U, task_environment_.GetPendingMainThreadTaskCount());

  // We now simulate a more common scenario.

  // Fast forward the time so that the task to upload a log runs. Since there
  // should be no logs, it should return early, and not re-post a task. I.e.,
  // there should be two tasks: one for querying independent logs from metrics
  // providers, and one for creating the next log.
  task_environment_.FastForwardBy(unsent_log_interval);
  EXPECT_FALSE(client.uploader()->is_uploading());
  EXPECT_FALSE(log_store->has_unsent_logs());
  EXPECT_EQ(2U, task_environment_.GetPendingMainThreadTaskCount());

  // Fast forward the time so that the next log is created. It should re-post
  // a task to create a new log, and should also re-start the upload scheduler.
  // I.e., there should be three (delayed) tasks: one for querying independent
  // logs from metrics providers, one for uploading an unsent log, and one for
  // creating the next log.
  // Note: The log is only created after |rotation_scheduler_interval| seconds,
  // and since we already fast forwarded by |unsent_log_interval| once, we only
  // need to fast forward by
  // |rotation_scheduler_interval| - |unsent_log_interval|.
  task_environment_.FastForwardBy(rotation_scheduler_interval -
                                  unsent_log_interval);
  EXPECT_TRUE(log_store->has_unsent_logs());
  EXPECT_EQ(3U, task_environment_.GetPendingMainThreadTaskCount());

  // Fast forward the time so that the task to upload a log runs.
  task_environment_.FastForwardBy(unsent_log_interval);
  EXPECT_TRUE(client.uploader()->is_uploading());
  // There should be two (delayed) tasks: one for querying independent logs from
  // metrics providers, and one for creating the next log. I.e., the task to
  // upload a log should be running, and should not be in the task queue
  // anymore.
  EXPECT_EQ(2U, task_environment_.GetPendingMainThreadTaskCount());

  // Simulate completing the upload. However, before doing so, add a dummy log
  // in order to test that when the upload task completes, if it detects another
  // log, it will re-post a task to upload the next log. I.e., after uploading
  // the log, there should be three (delayed) tasks: one for querying
  // independent logs from metrics providers, one for uploading an unsent log,
  // and one for creating the next log.
  log_store->StoreLog("dummy log", MetricsLog::LogType::ONGOING_LOG,
                      LogMetadata(),
                      MetricsLogsEventManager::CreateReason::kUnknown);
  EXPECT_EQ(2U, log_store->ongoing_log_count());
  client.uploader()->CompleteUpload(200);
  EXPECT_FALSE(client.uploader()->is_uploading());
  EXPECT_EQ(1U, log_store->ongoing_log_count());
  EXPECT_EQ(3U, task_environment_.GetPendingMainThreadTaskCount());

  // Fast forward the time so that the task to upload a log runs.
  task_environment_.FastForwardBy(unsent_log_interval);
  EXPECT_TRUE(client.uploader()->is_uploading());
  // There should be two (delayed) tasks: one for querying independent logs from
  // metrics providers, and one for creating the next log. I.e., the task to
  // upload a log should be running, and should not be in the task queue
  // anymore.
  EXPECT_EQ(2U, task_environment_.GetPendingMainThreadTaskCount());

  // Simulate completing the upload. Since there is no other log to be uploaded,
  // no task should be posted. I.e., there should only be two (delayed) tasks:
  // one for querying independent logs from metrics providers, and one.
  client.uploader()->CompleteUpload(200);
  EXPECT_FALSE(client.uploader()->is_uploading());
  EXPECT_FALSE(log_store->has_unsent_logs());
  EXPECT_EQ(2U, task_environment_.GetPendingMainThreadTaskCount());

  // Fast forward the time so that the task to create another log is run. It
  // should return early due to being idle (i.e., not create a log), and it
  // should not post another task to create another log. I.e., there should only
  // be one (delayed) task: one for querying independent logs from metrics
  // providers.
  // Note: The log is only created after |rotation_scheduler_interval| seconds,
  // and since we already fast forwarded by |unsent_log_interval| twice, we only
  // need to fast forward by
  // |rotation_scheduler_interval| - 2 * |unsent_log_interval|.
  task_environment_.FastForwardBy(rotation_scheduler_interval -
                                  2 * unsent_log_interval);
  EXPECT_FALSE(log_store->has_unsent_logs());
  EXPECT_EQ(1U, task_environment_.GetPendingMainThreadTaskCount());
}

TEST_F(MetricsServiceTest, LastLiveTimestamp) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  base::Time initial_last_live_time =
      GetLocalState()->GetTime(prefs::kStabilityBrowserLastLiveTimeStamp);

  service.InitializeMetricsRecordingState();
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log. Also verify that the test provider
  // was called when closing the log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());
  size_t num_pending_tasks = task_environment_.GetPendingMainThreadTaskCount();

  service.StartUpdatingLastLiveTimestamp();

  // Starting the update sequence should not write anything, but should
  // set up for a later write.
  EXPECT_EQ(
      initial_last_live_time,
      GetLocalState()->GetTime(prefs::kStabilityBrowserLastLiveTimeStamp));
  EXPECT_EQ(num_pending_tasks + 1,
            task_environment_.GetPendingMainThreadTaskCount());

  // Fast forward the time so that the task to update the "last alive timestamp"
  // runs.
  task_environment_.FastForwardBy(service.GetUpdateLastAliveTimestampDelay());

  // Verify that the time has updated in local state.
  base::Time updated_last_live_time =
      GetLocalState()->GetTime(prefs::kStabilityBrowserLastLiveTimeStamp);
  EXPECT_LT(initial_last_live_time, updated_last_live_time);

  // Double check that an update was scheduled again.
  task_environment_.FastForwardBy(service.GetUpdateLastAliveTimestampDelay());
  EXPECT_LT(
      updated_last_live_time,
      GetLocalState()->GetTime(prefs::kStabilityBrowserLastLiveTimeStamp));
}

// Verifies that when a cloned install is detected, logs are purged.
TEST_F(MetricsServiceTest, PurgeLogsOnClonedInstallDetected) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());
  service.InitializeMetricsRecordingState();

  // Store various logs.
  MetricsLogStore* test_log_store = service.LogStoreForTest();
  test_log_store->StoreLog("dummy log data", MetricsLog::ONGOING_LOG,
                           LogMetadata(),
                           MetricsLogsEventManager::CreateReason::kUnknown);
  test_log_store->StageNextLog();
  test_log_store->StoreLog("more dummy log data", MetricsLog::ONGOING_LOG,
                           LogMetadata(),
                           MetricsLogsEventManager::CreateReason::kUnknown);
  test_log_store->StoreLog("dummy stability log",
                           MetricsLog::INITIAL_STABILITY_LOG, LogMetadata(),
                           MetricsLogsEventManager::CreateReason::kUnknown);
  test_log_store->SetAlternateOngoingLogStore(InitializeTestLogStoreAndGet());
  test_log_store->StoreLog("dummy log for alternate ongoing log store",
                           MetricsLog::ONGOING_LOG, LogMetadata(),
                           MetricsLogsEventManager::CreateReason::kUnknown);
  EXPECT_TRUE(test_log_store->has_staged_log());
  EXPECT_TRUE(test_log_store->has_unsent_logs());

  ClonedInstallDetector* cloned_install_detector =
      GetMetricsStateManager()->cloned_install_detector_for_testing();

  static constexpr char kTestRawId[] = "test";
  // Hashed machine id for |kTestRawId|.
  static constexpr int kTestHashedId = 2216819;

  // Save a machine id that will not cause a clone to be detected.
  GetLocalState()->SetInteger(prefs::kMetricsMachineId, kTestHashedId);
  cloned_install_detector->SaveMachineId(GetLocalState(), base::Time::Now(),
                                         kTestRawId);
  // Verify that the logs are still present.
  EXPECT_TRUE(test_log_store->has_staged_log());
  EXPECT_TRUE(test_log_store->has_unsent_logs());

  // Save a machine id that will cause a clone to be detected.
  GetLocalState()->SetInteger(prefs::kMetricsMachineId, kTestHashedId + 1);
  cloned_install_detector->SaveMachineId(GetLocalState(), base::Time::Now(),
                                         kTestRawId);
  // Verify that the logs were purged.
  EXPECT_FALSE(test_log_store->has_staged_log());
  EXPECT_FALSE(test_log_store->has_unsent_logs());
}

#if BUILDFLAG(IS_CHROMEOS)
TEST_F(MetricsServiceTest,
       OngoingLogNotFlushedBeforeInitialLogWhenUserLogStoreSet) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  MetricsLogStore* test_log_store = service.LogStoreForTest();
  std::unique_ptr<TestUnsentLogStore> alternate_ongoing_log_store =
      InitializeTestLogStoreAndGet();
  TestUnsentLogStore* alternate_ongoing_log_store_ptr =
      alternate_ongoing_log_store.get();

  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(0u, test_log_store->ongoing_log_count());

  service.SetUserLogStore(std::move(alternate_ongoing_log_store));

  // Initial logs should not have been collected so the ongoing log being
  // recorded should not be flushed when a user log store is mounted.
  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(0u, test_log_store->ongoing_log_count());

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());
  // When the init task is complete, the first ongoing log should be created
  // in the alternate ongoing log store.
  EXPECT_EQ(0u, test_log_store->initial_log_count());
  EXPECT_EQ(0u, test_log_store->ongoing_log_count());
  EXPECT_EQ(1u, alternate_ongoing_log_store_ptr->size());
}

TEST_F(MetricsServiceTest,
       OngoingLogFlushedAfterInitialLogWhenUserLogStoreSet) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  MetricsLogStore* test_log_store = service.LogStoreForTest();
  std::unique_ptr<TestUnsentLogStore> alternate_ongoing_log_store =
      InitializeTestLogStoreAndGet();

  // Init state.
  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(0u, test_log_store->ongoing_log_count());

  // Fast forward the time by |initialization_delay|, which is when the pending
  // init tasks will run.
  base::TimeDelta initialization_delay = service.GetInitializationDelay();
  task_environment_.FastForwardBy(initialization_delay);
  EXPECT_EQ(TestMetricsService::INIT_TASK_DONE, service.state());

  // Fast forward the time until the MetricsRotationScheduler first runs, which
  // should complete the first ongoing log.
  // Note: The first log is only created after N = GetInitialIntervalSeconds()
  // seconds since the start, and since we already fast forwarded by
  // |initialization_delay| once, we only need to fast forward by
  // N - |initialization_delay|.
  task_environment_.FastForwardBy(
      base::Seconds(MetricsScheduler::GetInitialIntervalSeconds()) -
      initialization_delay);
  ASSERT_EQ(TestMetricsService::SENDING_LOGS, service.state());
  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(1u, test_log_store->ongoing_log_count());

  // User log store set post-init.
  service.SetUserLogStore(std::move(alternate_ongoing_log_store));

  // Another log should have been flushed from setting the user log store.
  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(2u, test_log_store->ongoing_log_count());
}

TEST_F(MetricsServiceTest, OngoingLogDiscardedAfterEarlyUnsetUserLogStore) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();
  // Start() will create the first ongoing log.
  service.Start();
  ASSERT_EQ(TestMetricsService::INIT_TASK_SCHEDULED, service.state());

  MetricsLogStore* test_log_store = service.LogStoreForTest();
  std::unique_ptr<TestUnsentLogStore> alternate_ongoing_log_store =
      InitializeTestLogStoreAndGet();

  ASSERT_EQ(0u, test_log_store->initial_log_count());
  ASSERT_EQ(0u, test_log_store->ongoing_log_count());

  service.SetUserLogStore(std::move(alternate_ongoing_log_store));

  // Unset the user log store before we started sending logs.
  base::UmaHistogramBoolean("Test.Before.Histogram", true);
  service.UnsetUserLogStore();
  base::UmaHistogramBoolean("Test.After.Histogram", true);

  // Verify that the current log was discarded.
  EXPECT_FALSE(service.GetCurrentLogForTest());

  // Verify that histograms from before unsetting the user log store were
  // flushed.
  EXPECT_EQ(0, GetHistogramDeltaTotalCount("Test.Before.Histogram"));
  EXPECT_EQ(1, GetHistogramDeltaTotalCount("Test.After.Histogram"));

  // Clean up histograms.
  base::StatisticsRecorder::ForgetHistogramForTesting("Test.Before.Histogram");
  base::StatisticsRecorder::ForgetHistogramForTesting("Test.After.Histogram");
}

TEST_F(MetricsServiceTest, UnsettingLogStoreShouldDisableRecording) {
  EnableMetricsReporting();
  TestMetricsServiceClient client;
  TestMetricsService service(GetMetricsStateManager(), &client,
                             GetLocalState());

  service.InitializeMetricsRecordingState();
  // Start() will register the service to start recording.
  service.Start();
  ASSERT_TRUE(service.recording_active());

  // Register, set and unset a log store.
  // This will clear the log file and thus should also stop recording.
  std::unique_ptr<TestUnsentLogStore> alternate_ongoing_log_store =
      InitializeTestLogStoreAndGet();
  service.SetUserLogStore(std::move(alternate_ongoing_log_store));
  service.UnsetUserLogStore();
  ASSERT_FALSE(service.recording_active());

  // This should not crash.
  base::RecordAction(base::UserMetricsAction("TestAction"));
}

#endif  // BUILDFLAG(IS_CHROMEOS)

}  // namespace metrics