Extract SyntheticTrialRegistry from MetricsService

components/variations/synthetic_trial_registry.h

Index: components/variations/synthetic_trial_registry.h
diff --git a/components/metrics/metrics_service.h b/components/variations/synthetic_trial_registry.h
similarity index 11%
copy from components/metrics/metrics_service.h
copy to components/variations/synthetic_trial_registry.h
index 08ac80eb9e765d29dec85fb6376ccdda189eeef3..be8e54e6b98b257f81a26f39180b4beafe89e3c5 100644
--- a/components/metrics/metrics_service.h
+++ b/components/variations/synthetic_trial_registry.h
@@ -1,233 +1,34 @@
-// 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.
 
-// This file defines a service that collects information about the user
-// experience in order to help improve future versions of the app.
+#ifndef COMPONENTS_VARIATIONS_SYNTHETIC_TRIAL_REGISTRY_H_
+#define COMPONENTS_VARIATIONS_SYNTHETIC_TRIAL_REGISTRY_H_
 
-#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"
 
-class PrefService;
-class PrefRegistrySimple;
-
-namespace base {
-class HistogramSamples;
-class PrefService;
-}
-
 namespace variations {
-struct ActiveGroupId;
-}
-
-namespace metrics {
 
-class MetricsRotationScheduler;
-class MetricsServiceAccessor;
-class MetricsServiceClient;
-class MetricsStateManager;
+struct ActiveGroupId;
 
-// See metrics_service.cc for a detailed description.
-class MetricsService : public base::HistogramFlattener {
+class 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;
-
-  // Initializes metrics recording state. Updates various bookkeeping values in
-  // prefs and sets up the scheduler. This is a separate function rather than
-  // being done by the constructor so that field trials could be created before
-  // this is run.
-  void InitializeMetricsRecordingState();
-
-  // Starts the metrics system, turning on recording and uploading of metrics.
-  // Should be called when starting up with metrics enabled, or when metrics
-  // are turned on.
-  void Start();
-
-  // Starts the metrics system in a special test-only mode. Metrics won't ever
-  // be uploaded or persisted in this mode, but metrics will be recorded in
-  // memory.
-  void StartRecordingForTests();
-
-  // Shuts down the metrics system. Should be called at shutdown, or if metrics
-  // are turned off.
-  void Stop();
-
-  // Enable/disable transmission of accumulated logs and crash reports (dumps).
-  // Calling Start() automatically enables reporting, but sending is
-  // asyncronous so this can be called immediately after Start() to prevent
-  // any uploading.
-  void EnableReporting();
-  void DisableReporting();
-
-  // Returns the client ID for this client, or the empty string if metrics
-  // recording is not currently running.
-  std::string GetClientId();
-
-  // Returns the install date of the application, in seconds since the epoch.
-  int64_t GetInstallDate();
-
-  // Returns the date at which the current metrics client ID was created as
-  // an int64_t containing seconds since the epoch.
-  int64_t GetMetricsReportingEnabledDate();
-
-  // Returns true if the last session exited cleanly.
-  bool WasLastShutdownClean() const;
-
-  // Registers local state prefs used by this class.
-  static void RegisterPrefs(PrefRegistrySimple* registry);
-
-  // HistogramFlattener:
-  void RecordDelta(const base::HistogramBase& histogram,
-                   const base::HistogramSamples& snapshot) override;
-  void InconsistencyDetected(
-      base::HistogramBase::Inconsistency problem) override;
-  void UniqueInconsistencyDetected(
-      base::HistogramBase::Inconsistency problem) override;
-  void InconsistencyDetectedInLoggedCount(int amount) override;
-
-  // This should be called when the application is not idle, i.e. the user seems
-  // to be interacting with the application.
-  void OnApplicationNotIdle();
-
-  // Invoked when we get a WM_SESSIONEND. This places a value in prefs that is
-  // reset when RecordCompletedSessionEnd is invoked.
-  void RecordStartOfSessionEnd();
-
-  // This should be called when the application is shutting down. It records
-  // that session end was successful.
-  void RecordCompletedSessionEnd();
-
-#if defined(OS_ANDROID) || defined(OS_IOS)
-  // Called when the application is going into background mode.
-  void OnAppEnterBackground();
-
-  // Called when the application is coming out of background mode.
-  void OnAppEnterForeground();
-#else
-  // Set the dirty flag, which will require a later call to LogCleanShutdown().
-  void LogNeedForCleanShutdown();
-#endif  // defined(OS_ANDROID) || defined(OS_IOS)
-
-  static void SetExecutionPhase(ExecutionPhase execution_phase,
-                                PrefService* local_state);
-
-  // Saves in the preferences if the crash report registration was successful.
-  // This count is eventually send via UMA logs.
-  void RecordBreakpadRegistration(bool success);
-
-  // Saves in the preferences if the browser is running under a debugger.
-  // This count is eventually send via UMA logs.
-  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();
+  SyntheticTrialRegistry();
+  ~SyntheticTrialRegistry();
 
   // 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);
+      std::vector<ActiveGroupId>* synthetic_trials);
 
   // Adds an observer to be notified when the synthetic trials list changes.
-  void AddSyntheticTrialObserver(variations::SyntheticTrialObserver* observer);
+  void AddSyntheticTrialObserver(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.
-  void ClearSavedStabilityMetrics();
-
-  // Pushes a log that has been generated by an external component.
-  void PushExternalLog(const std::string& log);
-
-  // Updates data usage tracking prefs with the specified values.
-  void UpdateMetricsUsagePrefs(const std::string& service_name,
-                               int message_size,
-                               bool is_cellular);
-
- protected:
-  // Exposed for testing.
-  MetricsLogManager* log_manager() { return &log_manager_; }
-  MetricsLogStore* log_store() {
-    return reporting_service_.metrics_log_store();
-  }
-
- private:
-  friend class MetricsServiceAccessor;
-
-  // The MetricsService has a lifecycle that is stored as a state.
-  // See metrics_service.cc for description of this lifecycle.
-  enum State {
-    INITIALIZED,          // Constructor was called.
-    INIT_TASK_SCHEDULED,  // Waiting for deferred init tasks to finish.
-    INIT_TASK_DONE,       // Waiting for timer to send initial log.
-    SENDING_LOGS,         // Sending logs an creating new ones when we run out.
-  };
-
-  enum ShutdownCleanliness {
-    CLEANLY_SHUTDOWN = 0xdeadbeef,
-    NEED_TO_SHUTDOWN = ~CLEANLY_SHUTDOWN
-  };
-
-  // 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;
+  void RemoveSyntheticTrialObserver(SyntheticTrialObserver* observer);
 
   // 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
@@ -238,8 +39,7 @@ class MetricsService : public base::HistogramFlattener {
   // 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);
+  void RegisterSyntheticFieldTrial(const SyntheticTrialGroup& trial_group);
 
   // Similar to RegisterSyntheticFieldTrial(), but registers a synthetic trial
   // that has multiple active groups for a given trial name hash. Any previous
@@ -248,205 +48,22 @@ class MetricsService : public base::HistogramFlattener {
       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
-  // call to this function.  Also updates the cumulative uptime metric (stored
-  // as a pref) for uninstall.  Uptimes are measured using TimeTicks, which
-  // guarantees that it is monotonic and does not jump if the user changes
-  // their clock.  The TimeTicks implementation also makes the clock not
-  // count time the computer is suspended.
-  void GetUptimes(PrefService* pref,
-                  base::TimeDelta* incremental_uptime,
-                  base::TimeDelta* uptime);
-
-  // Turns recording on or off.
-  // DisableRecording() also forces a persistent save of logging state (if
-  // anything has been recorded, or transmitted).
-  void EnableRecording();
-  void DisableRecording();
-
-  // If in_idle is true, sets idle_since_last_transmission to true.
-  // If in_idle is false and idle_since_last_transmission_ is true, sets
-  // idle_since_last_transmission to false and starts the timer (provided
-  // starting the timer is permitted).
-  void HandleIdleSinceLastTransmission(bool in_idle);
-
-  // Set up client ID, session ID, etc.
-  void InitializeMetricsState();
-
-  // Notifies providers when a new metrics log is created.
-  void NotifyOnDidCreateMetricsLog();
-
-  // Opens a new log for recording user experience metrics.
-  void OpenNewLog();
-
-  // Closes out the current log after adding any last information.
-  void CloseCurrentLog();
-
-  // Pushes the text of the current and staged logs into persistent storage.
-  // Called when Chrome shuts down.
-  void PushPendingLogsToPersistentStorage();
-
-  // Ensures that scheduler is running, assuming the current settings are such
-  // that metrics should be reported. If not, this is a no-op.
-  void StartSchedulerIfNecessary();
-
-  // Starts the process of uploading metrics data.
-  void StartScheduledUpload();
-
-  // Called by the client via a callback when final log info collection is
-  // complete.
-  void OnFinalLogInfoCollectionDone();
-
-  // Returns true if any of the registered metrics providers have critical
-  // stability metrics to report in an initial stability log.
-  bool ProvidersHaveInitialStabilityMetrics();
-
-  // Prepares the initial stability log, which is only logged when the previous
-  // run of Chrome crashed.  This log contains any stability metrics left over
-  // from that previous run, and only these stability metrics.  It uses the
-  // system profile from the previous session.  |prefs_previous_version| is used
-  // to validate the version number recovered from the system profile.  Returns
-  // true if a log was created.
-  bool PrepareInitialStabilityLog(const std::string& prefs_previous_version);
-
-  // Prepares the initial metrics log, which includes startup histograms and
-  // 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();
-
-  // Record complete list of stability histograms into the current log,
-  // i.e., histograms with the |kUmaStabilityHistogramFlag| flag set.
-  void RecordCurrentStabilityHistograms();
-
-  // Record a single independent profile and assocatied histogram from
-  // metrics providers. If this returns true, one was found and there may
-  // be more.
-  bool PrepareProviderMetricsLog();
-
-  // Records one independent histogram log and then reschedules itself to
-  // check for others. The interval is so as to not adversely impact the UI.
-  void PrepareProviderMetricsTask();
-
-  // Sub-service for uploading logs.
-  MetricsReportingService reporting_service_;
+      std::vector<ActiveGroupId>* synthetic_trials);
 
-  // Manager for the various in-flight logs.
-  MetricsLogManager log_manager_;
-
-  // |histogram_snapshot_manager_| prepares histogram deltas for transmission.
-  base::HistogramSnapshotManager histogram_snapshot_manager_;
-
-  // Used to manage various metrics reporting state prefs, such as client id,
-  // low entropy source and whether metrics reporting is enabled. Weak pointer.
-  MetricsStateManager* const state_manager_;
-
-  // Used to interact with the embedder. Weak pointer; must outlive |this|
-  // instance.
-  MetricsServiceClient* const client_;
-
-  // Registered metrics providers.
-  std::vector<std::unique_ptr<MetricsProvider>> metrics_providers_;
-
-  PrefService* local_state_;
-
-  base::ActionCallback action_callback_;
-
-  // Indicate whether recording and reporting are currently happening.
-  // These should not be set directly, but by calling SetRecording and
-  // SetReporting.
-  RecordingState recording_state_;
-
-  // Indicate whether test mode is enabled, where the initial log should never
-  // be cut, and logs are neither persisted nor uploaded.
-  bool test_mode_active_;
-
-  // The progression of states made by the browser are recorded in the following
-  // state.
-  State state_;
-
-  // The initial metrics log, used to record startup metrics (histograms and
-  // profiler data). Note that if a crash occurred in the previous session, an
-  // initial stability log may be sent before this.
-  std::unique_ptr<MetricsLog> initial_metrics_log_;
-
-  // Whether the MetricsService object has received any notifications since
-  // the last time a transmission was sent.
-  bool idle_since_last_transmission_;
-
-  // A number that identifies the how many times the app has been launched.
-  int session_id_;
-
-  // 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_;
+ private:
+  // Notifies observers on a synthetic trial list change.
+  void NotifySyntheticTrialObservers();
 
   // Field trial groups that map to Chrome configuration states.
-  SyntheticTrialGroups synthetic_trial_groups_;
+  std::vector<SyntheticTrialGroup> 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);
+  base::ObserverList<SyntheticTrialObserver> synthetic_trial_observer_list_;
 };
 
-}  // namespace metrics
+}  // namespace variations
 
-#endif  // COMPONENTS_METRICS_METRICS_SERVICE_H_
+#endif  // COMPONENTS_VARIATIONS_SYNTHETIC_TRIAL_REGISTRY_H_