Extract SyntheticTrialRegistry from MetricsService

components/metrics/metrics_service.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines a service that collects information about the user
 // experience in order to help improve future versions of the app.
 
 #ifndef COMPONENTS_METRICS_METRICS_SERVICE_H_
 #define COMPONENTS_METRICS_METRICS_SERVICE_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_flattener.h"
 #include "base/metrics/histogram_snapshot_manager.h"
 #include "base/metrics/user_metrics.h"
-#include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "components/metrics/clean_exit_beacon.h"
 #include "components/metrics/execution_phase.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_log_manager.h"
 #include "components/metrics/metrics_log_store.h"
 #include "components/metrics/metrics_provider.h"
 #include "components/metrics/metrics_reporting_service.h"
 #include "components/metrics/net/network_metrics_provider.h"
-#include "components/variations/synthetic_trials.h"
+#include "components/variations/synthetic_trial_registry.h"
 
 class PrefService;
 class PrefRegistrySimple;
 
 namespace base {
 class HistogramSamples;
 class PrefService;
 }
 
-namespace variations {
-struct ActiveGroupId;
-}
-
 namespace metrics {
 
 class MetricsRotationScheduler;
 class MetricsServiceAccessor;
 class MetricsServiceClient;
 class MetricsStateManager;
 
 // See metrics_service.cc for a detailed description.
-class MetricsService : public base::HistogramFlattener {
+class MetricsService : public base::HistogramFlattener,
+                       public variations::SyntheticTrialRegistry {
  public:
   // Creates the MetricsService with the given |state_manager|, |client|, and
   // |local_state|.  Does not take ownership of the paramaters; instead stores
   // a weak pointer to each. Caller should ensure that the parameters are valid
   // for the lifetime of this class.
   MetricsService(MetricsStateManager* state_manager,
                  MetricsServiceClient* client,
                  PrefService* local_state);
   ~MetricsService() override;
 
@@ skipping 85 matching lines @@
   void RecordBreakpadHasDebugger(bool has_debugger);
 
   bool recording_active() const;
   bool reporting_active() const;
   bool has_unsent_logs() const;
 
   // Redundant test to ensure that we are notified of a clean exit.
   // This value should be true when process has completed shutdown.
   static bool UmaMetricsProperlyShutdown();
 
-  // Public accessor that returns the list of synthetic field trials. It must
-  // only be used for testing.
-  void GetCurrentSyntheticFieldTrialsForTesting(
-      std::vector<variations::ActiveGroupId>* synthetic_trials);
-
-  // Adds an observer to be notified when the synthetic trials list changes.
-  void AddSyntheticTrialObserver(variations::SyntheticTrialObserver* observer);
-
-  // Removes an existing observer of synthetic trials list changes.
-  void RemoveSyntheticTrialObserver(
-      variations::SyntheticTrialObserver* observer);
-
   // Register the specified |provider| to provide additional metrics into the
   // UMA log. Should be called during MetricsService initialization only.
   void RegisterMetricsProvider(std::unique_ptr<MetricsProvider> provider);
 
   // Check if this install was cloned or imaged from another machine. If a
   // clone is detected, reset the client id and low entropy source. This
   // should not be called more than once.
   void CheckForClonedInstall();
 
   // Clears the stability metrics that are saved in local state.
@@ skipping 33 matching lines @@
 
   // The current state of recording for the MetricsService. The state is UNSET
   // until set to something else, at which point it remains INACTIVE or ACTIVE
   // for the lifetime of the object.
   enum RecordingState {
     INACTIVE,
     ACTIVE,
     UNSET
   };
 
-  typedef std::vector<variations::SyntheticTrialGroup> SyntheticTrialGroups;
-
-  // Registers a field trial name and group to be used to annotate a UMA report
-  // with a particular Chrome configuration state. A UMA report will be
-  // annotated with this trial group if and only if all events in the report
-  // were created after the trial is registered. Only one group name may be
-  // registered at a time for a given trial_name. Only the last group name that
-  // is registered for a given trial name will be recorded. The values passed
-  // in must not correspond to any real field trial in the code.
-  // Note: Should not be used to replace trials that were registered with
-  // RegisterMultiGroupSyntheticFieldTrial().
-  void RegisterSyntheticFieldTrial(
-      const variations::SyntheticTrialGroup& trial_group);
-
-  // Similar to RegisterSyntheticFieldTrial(), but registers a synthetic trial
-  // that has multiple active groups for a given trial name hash. Any previous
-  // groups registered for |trial_name_hash| will be replaced.
-  void RegisterSyntheticMultiGroupFieldTrial(
-      uint32_t trial_name_hash,
-      const std::vector<uint32_t>& group_name_hashes);
-
   // Calls into the client to initialize some system profile metrics.
   void StartInitTask();
 
   // Callback that moves the state to INIT_TASK_DONE. When this is called, the
   // state should be INIT_TASK_SCHEDULED.
   void FinishedInitTask();
 
   void OnUserAction(const std::string& action);
 
   // Get the amount of uptime since this process started and since the last
@@ skipping 61 matching lines @@
   // profiler data, as well as incremental stability-related metrics.
   void PrepareInitialMetricsLog();
 
   // Reads, increments and then sets the specified long preference that is
   // stored as a string.
   void IncrementLongPrefsValue(const char* path);
 
   // Records that the browser was shut down cleanly.
   void LogCleanShutdown(bool end_completed);
 
-  // Notifies observers on a synthetic trial list change.
-  void NotifySyntheticTrialObservers();
-
-  // Returns a list of synthetic field trials that are older than |time|.
-  void GetSyntheticFieldTrialsOlderThan(
-      base::TimeTicks time,
-      std::vector<variations::ActiveGroupId>* synthetic_trials);
-
   // Creates a new MetricsLog instance with the given |log_type|.
   std::unique_ptr<MetricsLog> CreateLog(MetricsLog::LogType log_type);
 
   // Records the current environment (system profile) in |log|.
   void RecordCurrentEnvironment(MetricsLog* log);
 
   // Record complete list of histograms into the current log.
   // Called when we close a log.
   void RecordCurrentHistograms();
 
@@ skipping 61 matching lines @@
 
   // The scheduler for determining when log rotations should happen.
   std::unique_ptr<MetricsRotationScheduler> rotation_scheduler_;
 
   // Stores the time of the first call to |GetUptimes()|.
   base::TimeTicks first_updated_time_;
 
   // Stores the time of the last call to |GetUptimes()|.
   base::TimeTicks last_updated_time_;
 
-  // Field trial groups that map to Chrome configuration states.
-  SyntheticTrialGroups synthetic_trial_groups_;
-
-  // List of observers of |synthetic_trial_groups_| changes.
-  base::ObserverList<variations::SyntheticTrialObserver>
-      synthetic_trial_observer_list_;
-
   // Redundant marker to check that we completed our shutdown, and set the
   // exited-cleanly bit in the prefs.
   static ShutdownCleanliness clean_shutdown_status_;
 
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, IsPluginProcess);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest,
                            PermutedEntropyCacheClearedWhenLowEntropyReset);
-  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, RegisterSyntheticTrial);
-  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest,
-                           RegisterSyntheticMultiGroupFieldTrial);
-  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest,
-                           GetSyntheticFieldTrialActiveGroups);
 
   base::ThreadChecker thread_checker_;
 
   // Weak pointers factory used to post task on different threads. All weak
   // pointers managed by this factory have the same lifetime as MetricsService.
   base::WeakPtrFactory<MetricsService> self_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsService);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_METRICS_SERVICE_H_