Extract SyntheticTrialRegistry from MetricsService

components/variations/synthetic_trial_registry_unittest.cc

Index: components/variations/synthetic_trial_registry_unittest.cc
diff --git a/components/metrics/metrics_service_unittest.cc b/components/variations/synthetic_trial_registry_unittest.cc
similarity index 17%
copy from components/metrics/metrics_service_unittest.cc
copy to components/variations/synthetic_trial_registry_unittest.cc
index 3be79acb1dac9fb4979977de55e3371ad986646d..632aa3f95b919b5782dd18bddaef48c7f094c555 100644
--- a/components/metrics/metrics_service_unittest.cc
+++ b/components/variations/synthetic_trial_registry_unittest.cc
@@ -1,376 +1,68 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
+// 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.
 
-#include "components/metrics/metrics_service.h"
+#include "components/variations/synthetic_trial_registry.h"
 
-#include <stdint.h>
-
-#include <algorithm>
-#include <memory>
-#include <string>
-
-#include "base/bind.h"
-#include "base/macros.h"
-#include "base/message_loop/message_loop.h"
-#include "base/metrics/metrics_hashes.h"
-#include "base/metrics/statistics_recorder.h"
-#include "base/metrics/user_metrics.h"
-#include "base/stl_util.h"
-#include "base/strings/string16.h"
 #include "base/strings/stringprintf.h"
-#include "base/test/scoped_feature_list.h"
-#include "base/test/test_simple_task_runner.h"
-#include "base/threading/platform_thread.h"
-#include "base/threading/thread_task_runner_handle.h"
-#include "components/metrics/client_info.h"
-#include "components/metrics/environment_recorder.h"
-#include "components/metrics/metrics_log.h"
-#include "components/metrics/metrics_pref_names.h"
-#include "components/metrics/metrics_state_manager.h"
-#include "components/metrics/metrics_upload_scheduler.h"
-#include "components/metrics/test_enabled_state_provider.h"
-#include "components/metrics/test_metrics_provider.h"
-#include "components/metrics/test_metrics_service_client.h"
-#include "components/prefs/testing_pref_service.h"
 #include "components/variations/active_field_trials.h"
 #include "components/variations/metrics_util.h"
 #include "components/variations/synthetic_trials_active_group_id_provider.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "third_party/zlib/google/compression_utils.h"
 
-namespace metrics {
+namespace variations {
 
 namespace {
 
-void StoreNoClientInfoBackup(const ClientInfo& /* client_info */) {
-}
-
-std::unique_ptr<ClientInfo> ReturnNoBackup() {
-  return std::unique_ptr<ClientInfo>();
-}
-
-class TestMetricsService : public MetricsService {
+class SyntheticTrialRegistryTest : public ::testing::Test {
  public:
-  TestMetricsService(MetricsStateManager* state_manager,
-                     MetricsServiceClient* client,
-                     PrefService* local_state)
-      : MetricsService(state_manager, client, local_state) {}
-  ~TestMetricsService() override {}
-
-  using MetricsService::log_manager;
-  using MetricsService::log_store;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(TestMetricsService);
-};
-
-class TestMetricsLog : public MetricsLog {
- public:
-  TestMetricsLog(const std::string& client_id,
-                 int session_id,
-                 MetricsServiceClient* client,
-                 PrefService* local_state)
-      : MetricsLog(client_id,
-                   session_id,
-                   MetricsLog::ONGOING_LOG,
-                   client,
-                   local_state) {}
-
-  ~TestMetricsLog() override {}
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(TestMetricsLog);
-};
-
-class MetricsServiceTest : public testing::Test {
- public:
-  MetricsServiceTest()
-      : task_runner_(new base::TestSimpleTaskRunner),
-        task_runner_handle_(task_runner_),
-        enabled_state_provider_(new TestEnabledStateProvider(false, false)) {
-    base::SetRecordActionTaskRunner(task_runner_);
-    MetricsService::RegisterPrefs(testing_local_state_.registry());
-  }
-
-  ~MetricsServiceTest() override {
-    MetricsService::SetExecutionPhase(ExecutionPhase::UNINITIALIZED_PHASE,
-                                      GetLocalState());
-  }
-
-  MetricsStateManager* GetMetricsStateManager() {
-    // 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(), base::string16(),
-          base::Bind(&StoreNoClientInfoBackup), base::Bind(&ReturnNoBackup));
-    }
-    return metrics_state_manager_.get();
-  }
-
-  PrefService* GetLocalState() { return &testing_local_state_; }
-
-  // Sets metrics reporting as enabled for testing.
-  void EnableMetricsReporting() {
-    enabled_state_provider_->set_consent(true);
-    enabled_state_provider_->set_enabled(true);
-  }
-
-  // Waits until base::TimeTicks::Now() no longer equals |value|. This should
-  // take between 1-15ms per the documented resolution of base::TimeTicks.
-  void WaitUntilTimeChanges(const base::TimeTicks& value) {
-    while (base::TimeTicks::Now() == value) {
-      base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(1));
-    }
-  }
-
   // Returns true if there is a synthetic trial in the given vector that matches
   // the given trial name and trial group; returns false otherwise.
-  bool HasSyntheticTrial(
-      const std::vector<variations::ActiveGroupId>& synthetic_trials,
-      const std::string& trial_name,
-      const std::string& trial_group) {
-    uint32_t trial_name_hash = HashName(trial_name);
-    uint32_t trial_group_hash = HashName(trial_group);
-    for (const variations::ActiveGroupId& trial : synthetic_trials) {
+  bool HasSyntheticTrial(const std::vector<ActiveGroupId>& synthetic_trials,
+                         const std::string& trial_name,
+                         const std::string& trial_group) {
+    uint32_t trial_name_hash = metrics::HashName(trial_name);
+    uint32_t trial_group_hash = metrics::HashName(trial_group);
+    for (const ActiveGroupId& trial : synthetic_trials) {
       if (trial.name == trial_name_hash && trial.group == trial_group_hash)
         return true;
     }
     return false;
   }
 
-  // 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;
-    base::StatisticsRecorder::Histograms histograms;
-    base::StatisticsRecorder::GetHistograms(&histograms);
-    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_EQ(kStabilityFlags, histogram->flags() & kStabilityFlags) << hash;
+  // Waits until base::TimeTicks::Now() no longer equals |value|. This should
+  // take between 1-15ms per the documented resolution of base::TimeTicks.
+  void WaitUntilTimeChanges(const base::TimeTicks& value) {
+    while (base::TimeTicks::Now() == value) {
+      base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(1));
     }
   }
-
- protected:
-  scoped_refptr<base::TestSimpleTaskRunner> task_runner_;
-  base::ThreadTaskRunnerHandle task_runner_handle_;
-  base::test::ScopedFeatureList feature_list_;
-
- private:
-  std::unique_ptr<TestEnabledStateProvider> enabled_state_provider_;
-  TestingPrefServiceSimple testing_local_state_;
-  std::unique_ptr<MetricsStateManager> metrics_state_manager_;
-
-  DISALLOW_COPY_AND_ASSIGN(MetricsServiceTest);
 };
 
 }  // namespace
 
-TEST_F(MetricsServiceTest, InitialStabilityLogAfterCleanShutDown) {
-  EnableMetricsReporting();
-  GetLocalState()->SetBoolean(prefs::kStabilityExitedCleanly, true);
-
-  TestMetricsServiceClient client;
-  TestMetricsService service(
-      GetMetricsStateManager(), &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 HasInitialStabilityMetrics() 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());
-}
-
-TEST_F(MetricsServiceTest, InitialStabilityLogAtProviderRequest) {
-  EnableMetricsReporting();
-
-  // Save an existing system profile to prefs, to correspond to what would be
-  // saved from a previous session.
-  TestMetricsServiceClient client;
-  TestMetricsLog log("client", 1, &client, GetLocalState());
-  log.RecordEnvironment(std::vector<std::unique_ptr<MetricsProvider>>(),
-                        std::vector<variations::ActiveGroupId>(), 0, 0);
-
-  // 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());
-
-  // Set the clean exit flag, as that will otherwise cause a stabilty
-  // log to be produced, irrespective provider requests.
-  GetLocalState()->SetBoolean(prefs::kStabilityExitedCleanly, true);
-
-  TestMetricsService service(
-      GetMetricsStateManager(), &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* log_store = service.log_store();
-  EXPECT_TRUE(log_store->has_unsent_logs());
-  EXPECT_FALSE(log_store->has_staged_log());
-
-  // Ensure that HasInitialStabilityMetrics() 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.
-  log_store->StageNextLog();
-  EXPECT_TRUE(log_store->has_staged_log());
-
-  std::string uncompressed_log;
-  EXPECT_TRUE(
-      compression::GzipUncompress(log_store->staged_log(), &uncompressed_log));
-
-  ChromeUserMetricsExtension uma_log;
-  EXPECT_TRUE(uma_log.ParseFromString(uncompressed_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());
-  EXPECT_EQ(0, uma_log.profiler_event_size());
-  EXPECT_EQ(0, uma_log.perf_data_size());
-  CheckForNonStabilityHistograms(uma_log);
-
-  // As there wasn't an unclean shutdown, this log has zero crash count.
-  EXPECT_EQ(0, uma_log.system_profile().stability().crash_count());
-}
-
-TEST_F(MetricsServiceTest, InitialStabilityLogAfterCrash) {
-  EnableMetricsReporting();
-  GetLocalState()->ClearPref(prefs::kStabilityExitedCleanly);
-
-  // 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;
-  TestMetricsLog log("client", 1, &client, GetLocalState());
-  log.RecordEnvironment(std::vector<std::unique_ptr<MetricsProvider>>(),
-                        std::vector<variations::ActiveGroupId>(), 0, 0);
-
-  // 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());
-
-  GetLocalState()->SetBoolean(prefs::kStabilityExitedCleanly, false);
-
-  TestMetricsService service(
-      GetMetricsStateManager(), &client, GetLocalState());
-  // Add a provider.
-  TestMetricsProvider* test_provider = new TestMetricsProvider();
-  service.RegisterMetricsProvider(
-      std::unique_ptr<MetricsProvider>(test_provider));
-  service.InitializeMetricsRecordingState();
-
-  // The initial stability log should be generated and persisted in unsent logs.
-  MetricsLogStore* log_store = service.log_store();
-  EXPECT_TRUE(log_store->has_unsent_logs());
-  EXPECT_FALSE(log_store->has_staged_log());
-
-  // Ensure that HasInitialStabilityMetrics() 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.
-  log_store->StageNextLog();
-  EXPECT_TRUE(log_store->has_staged_log());
-
-  std::string uncompressed_log;
-  EXPECT_TRUE(
-      compression::GzipUncompress(log_store->staged_log(), &uncompressed_log));
-
-  ChromeUserMetricsExtension uma_log;
-  EXPECT_TRUE(uma_log.ParseFromString(uncompressed_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());
-  EXPECT_EQ(0, uma_log.profiler_event_size());
-  EXPECT_EQ(0, uma_log.perf_data_size());
-  CheckForNonStabilityHistograms(uma_log);
-
-  EXPECT_EQ(1, uma_log.system_profile().stability().crash_count());
-}
-
-TEST_F(MetricsServiceTest, RegisterSyntheticTrial) {
-  TestMetricsServiceClient client;
-  MetricsService service(GetMetricsStateManager(), &client, GetLocalState());
+TEST_F(SyntheticTrialRegistryTest, RegisterSyntheticTrial) {
+  SyntheticTrialRegistry registry;
 
   // Add two synthetic trials and confirm that they show up in the list.
-  variations::SyntheticTrialGroup trial1(HashName("TestTrial1"),
-                                         HashName("Group1"));
-  service.RegisterSyntheticFieldTrial(trial1);
+  SyntheticTrialGroup trial1(metrics::HashName("TestTrial1"),
+                             metrics::HashName("Group1"));
+  registry.RegisterSyntheticFieldTrial(trial1);
 
-  variations::SyntheticTrialGroup trial2(HashName("TestTrial2"),
-                                         HashName("Group2"));
-  service.RegisterSyntheticFieldTrial(trial2);
+  SyntheticTrialGroup trial2(metrics::HashName("TestTrial2"),
+                             metrics::HashName("Group2"));
+  registry.RegisterSyntheticFieldTrial(trial2);
   // Ensure that time has advanced by at least a tick before proceeding.
   WaitUntilTimeChanges(base::TimeTicks::Now());
 
-  service.log_manager_.BeginLoggingWithLog(std::unique_ptr<MetricsLog>(
-      new MetricsLog("clientID", 1, MetricsLog::INITIAL_STABILITY_LOG, &client,
-                     GetLocalState())));
   // Save the time when the log was started (it's okay for this to be greater
   // than the time recorded by the above call since it's used to ensure the
   // value changes).
   const base::TimeTicks begin_log_time = base::TimeTicks::Now();
 
-  std::vector<variations::ActiveGroupId> synthetic_trials;
-  service.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
-                                           &synthetic_trials);
+  std::vector<ActiveGroupId> synthetic_trials;
+  registry.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
+                                            &synthetic_trials);
   EXPECT_EQ(2U, synthetic_trials.size());
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial1", "Group1"));
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial2", "Group2"));
@@ -379,18 +71,18 @@ TEST_F(MetricsServiceTest, RegisterSyntheticTrial) {
   WaitUntilTimeChanges(begin_log_time);
 
   // Change the group for the first trial after the log started.
-  variations::SyntheticTrialGroup trial3(HashName("TestTrial1"),
-                                         HashName("Group2"));
-  service.RegisterSyntheticFieldTrial(trial3);
-  service.GetSyntheticFieldTrialsOlderThan(begin_log_time, &synthetic_trials);
+  SyntheticTrialGroup trial3(metrics::HashName("TestTrial1"),
+                             metrics::HashName("Group2"));
+  registry.RegisterSyntheticFieldTrial(trial3);
+  registry.GetSyntheticFieldTrialsOlderThan(begin_log_time, &synthetic_trials);
   EXPECT_EQ(1U, synthetic_trials.size());
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial2", "Group2"));
 
   // Add a new trial after the log started and confirm that it doesn't show up.
-  variations::SyntheticTrialGroup trial4(HashName("TestTrial3"),
-                                         HashName("Group3"));
-  service.RegisterSyntheticFieldTrial(trial4);
-  service.GetSyntheticFieldTrialsOlderThan(begin_log_time, &synthetic_trials);
+  SyntheticTrialGroup trial4(metrics::HashName("TestTrial3"),
+                             metrics::HashName("Group3"));
+  registry.RegisterSyntheticFieldTrial(trial4);
+  registry.GetSyntheticFieldTrialsOlderThan(begin_log_time, &synthetic_trials);
   EXPECT_EQ(1U, synthetic_trials.size());
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial2", "Group2"));
 
@@ -398,170 +90,79 @@ TEST_F(MetricsServiceTest, RegisterSyntheticTrial) {
   WaitUntilTimeChanges(base::TimeTicks::Now());
 
   // Start a new log and ensure all three trials appear in it.
-  service.log_manager_.FinishCurrentLog(service.log_store());
-  service.log_manager_.BeginLoggingWithLog(
-      std::unique_ptr<MetricsLog>(new MetricsLog(
-          "clientID", 1, MetricsLog::ONGOING_LOG, &client, GetLocalState())));
-  service.GetSyntheticFieldTrialsOlderThan(
-      service.log_manager_.current_log()->creation_time(), &synthetic_trials);
+  registry.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
+                                            &synthetic_trials);
   EXPECT_EQ(3U, synthetic_trials.size());
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial1", "Group2"));
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial2", "Group2"));
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial3", "Group3"));
-  service.log_manager_.FinishCurrentLog(service.log_store());
 }
 
-TEST_F(MetricsServiceTest, RegisterSyntheticMultiGroupFieldTrial) {
-  TestMetricsServiceClient client;
-  MetricsService service(GetMetricsStateManager(), &client, GetLocalState());
+TEST_F(SyntheticTrialRegistryTest, RegisterSyntheticMultiGroupFieldTrial) {
+  SyntheticTrialRegistry registry;
 
   // Register a synthetic trial TestTrial1 with groups A and B.
-  uint32_t trial_name_hash = HashName("TestTrial1");
-  std::vector<uint32_t> group_name_hashes = {HashName("A"), HashName("B")};
-  service.RegisterSyntheticMultiGroupFieldTrial(trial_name_hash,
-                                                group_name_hashes);
+  uint32_t trial_name_hash = metrics::HashName("TestTrial1");
+  std::vector<uint32_t> group_name_hashes = {metrics::HashName("A"),
+                                             metrics::HashName("B")};
+  registry.RegisterSyntheticMultiGroupFieldTrial(trial_name_hash,
+                                                 group_name_hashes);
   // Ensure that time has advanced by at least a tick before proceeding.
   WaitUntilTimeChanges(base::TimeTicks::Now());
 
-  service.log_manager_.BeginLoggingWithLog(std::unique_ptr<MetricsLog>(
-      new MetricsLog("clientID", 1, MetricsLog::INITIAL_STABILITY_LOG, &client,
-                     GetLocalState())));
-
-  std::vector<variations::ActiveGroupId> synthetic_trials;
-  service.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
-                                           &synthetic_trials);
+  std::vector<ActiveGroupId> synthetic_trials;
+  registry.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
+                                            &synthetic_trials);
   EXPECT_EQ(2U, synthetic_trials.size());
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial1", "A"));
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial1", "B"));
 
   // Change the group for the trial to a single group.
-  group_name_hashes = {HashName("X")};
-  service.RegisterSyntheticMultiGroupFieldTrial(trial_name_hash,
-                                                group_name_hashes);
+  group_name_hashes = {metrics::HashName("X")};
+  registry.RegisterSyntheticMultiGroupFieldTrial(trial_name_hash,
+                                                 group_name_hashes);
   // Ensure that time has advanced by at least a tick before proceeding.
   WaitUntilTimeChanges(base::TimeTicks::Now());
 
-  service.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
-                                           &synthetic_trials);
+  registry.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
+                                            &synthetic_trials);
   EXPECT_EQ(1U, synthetic_trials.size());
   EXPECT_TRUE(HasSyntheticTrial(synthetic_trials, "TestTrial1", "X"));
 
   // Register a trial with no groups, which should effectively remove the trial.
   group_name_hashes.clear();
-  service.RegisterSyntheticMultiGroupFieldTrial(trial_name_hash,
-                                                group_name_hashes);
+  registry.RegisterSyntheticMultiGroupFieldTrial(trial_name_hash,
+                                                 group_name_hashes);
   // Ensure that time has advanced by at least a tick before proceeding.
   WaitUntilTimeChanges(base::TimeTicks::Now());
 
-  service.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
-                                           &synthetic_trials);
-  service.log_manager_.FinishCurrentLog(service.log_store());
-}
-
-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());
-}
-
-TEST_F(MetricsServiceTest, SplitRotation) {
-  TestMetricsServiceClient client;
-  TestMetricsService service(GetMetricsStateManager(), &client,
-                             GetLocalState());
-  service.InitializeMetricsRecordingState();
-  service.Start();
-  // Rotation loop should create a log and mark state as idle.
-  // Upload loop should start upload or be restarted.
-  // The independent-metrics upload job will be started and always be a task.
-  task_runner_->RunPendingTasks();
-  // Rotation loop should terminated due to being idle.
-  // Upload loop should start uploading if it isn't already.
-  task_runner_->RunPendingTasks();
-  EXPECT_TRUE(client.uploader()->is_uploading());
-  EXPECT_EQ(1U, task_runner_->NumPendingTasks());
-  service.OnApplicationNotIdle();
-  EXPECT_TRUE(client.uploader()->is_uploading());
-  EXPECT_EQ(2U, task_runner_->NumPendingTasks());
-  // Log generation should be suppressed due to unsent log.
-  // Idle state should not be reset.
-  task_runner_->RunPendingTasks();
-  EXPECT_TRUE(client.uploader()->is_uploading());
-  EXPECT_EQ(2U, task_runner_->NumPendingTasks());
-  // Make sure idle state was not reset.
-  task_runner_->RunPendingTasks();
-  EXPECT_TRUE(client.uploader()->is_uploading());
-  EXPECT_EQ(2U, task_runner_->NumPendingTasks());
-  // Upload should not be rescheduled, since there are no other logs.
-  client.uploader()->CompleteUpload(200);
-  EXPECT_FALSE(client.uploader()->is_uploading());
-  EXPECT_EQ(2U, task_runner_->NumPendingTasks());
-  // Running should generate a log, restart upload loop, and mark idle.
-  task_runner_->RunPendingTasks();
-  EXPECT_FALSE(client.uploader()->is_uploading());
-  EXPECT_EQ(3U, task_runner_->NumPendingTasks());
-  // Upload should start, and rotation loop should idle out.
-  task_runner_->RunPendingTasks();
-  EXPECT_TRUE(client.uploader()->is_uploading());
-  EXPECT_EQ(1U, task_runner_->NumPendingTasks());
-  // Uploader should reschedule when there is another log available.
-  service.PushExternalLog("Blah");
-  client.uploader()->CompleteUpload(200);
-  EXPECT_FALSE(client.uploader()->is_uploading());
-  EXPECT_EQ(2U, task_runner_->NumPendingTasks());
-  // Upload should start.
-  task_runner_->RunPendingTasks();
-  EXPECT_TRUE(client.uploader()->is_uploading());
-  EXPECT_EQ(1U, task_runner_->NumPendingTasks());
+  registry.GetSyntheticFieldTrialsOlderThan(base::TimeTicks::Now(),
+                                            &synthetic_trials);
 }
 
-TEST_F(MetricsServiceTest, GetSyntheticFieldTrialActiveGroups) {
-  TestMetricsServiceClient client;
-  MetricsService service(GetMetricsStateManager(), &client, GetLocalState());
+TEST_F(SyntheticTrialRegistryTest, GetSyntheticFieldTrialActiveGroups) {
+  SyntheticTrialRegistry registry;
 
   // Instantiate and setup the corresponding singleton observer which tracks the
   // creation of all SyntheticTrialGroups.
-  service.AddSyntheticTrialObserver(
-      variations::SyntheticTrialsActiveGroupIdProvider::GetInstance());
+  registry.AddSyntheticTrialObserver(
+      SyntheticTrialsActiveGroupIdProvider::GetInstance());
 
   // Add two synthetic trials and confirm that they show up in the list.
-  variations::SyntheticTrialGroup trial1(HashName("TestTrial1"),
-                                         HashName("Group1"));
-  service.RegisterSyntheticFieldTrial(trial1);
+  SyntheticTrialGroup trial1(metrics::HashName("TestTrial1"),
+                             metrics::HashName("Group1"));
+  registry.RegisterSyntheticFieldTrial(trial1);
 
-  variations::SyntheticTrialGroup trial2(HashName("TestTrial2"),
-                                         HashName("Group2"));
-  service.RegisterSyntheticFieldTrial(trial2);
+  SyntheticTrialGroup trial2(metrics::HashName("TestTrial2"),
+                             metrics::HashName("Group2"));
+  registry.RegisterSyntheticFieldTrial(trial2);
 
   // Ensure that time has advanced by at least a tick before proceeding.
   WaitUntilTimeChanges(base::TimeTicks::Now());
 
   // Now get the list of currently active groups.
   std::vector<std::string> output;
-  variations::GetSyntheticTrialGroupIdsAsString(&output);
+  GetSyntheticTrialGroupIdsAsString(&output);
   EXPECT_EQ(2U, output.size());
 
   std::string trial1_hash =
@@ -573,4 +174,4 @@ TEST_F(MetricsServiceTest, GetSyntheticFieldTrialActiveGroups) {
   EXPECT_TRUE(base::ContainsValue(output, trial2_hash));
 }
 
-}  // namespace metrics
+}  // namespace variations