Move MetricsStateManager into the Metrics component.

chrome/browser/metrics/metrics_state_manager.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.
-
-#ifndef CHROME_BROWSER_METRICS_METRICS_STATE_MANAGER_H_
-#define CHROME_BROWSER_METRICS_METRICS_STATE_MANAGER_H_
-
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/callback.h"
-#include "base/gtest_prod_util.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/metrics/field_trial.h"
-
-class PrefService;
-class PrefRegistrySimple;
-
-namespace metrics {
-
-class ClonedInstallDetector;
-
-// Responsible for managing MetricsService state prefs, specifically the UMA
-// client id and low entropy source. Code outside the metrics directory should
-// not be instantiating or using this class directly.
-class MetricsStateManager {
- public:
-  virtual ~MetricsStateManager();
-
-  // Returns true if the user opted in to sending metric reports.
-  bool IsMetricsReportingEnabled();
-
-  // Returns the client ID for this client, or the empty string if the user is
-  // not opted in to metrics reporting.
-  const std::string& client_id() const { return client_id_; }
-
-  // Forces the client ID to be generated. This is useful in case it's needed
-  // before recording.
-  void ForceClientIdCreation();
-
-  // Checks if this install was cloned or imaged from another machine. If a
-  // clone is detected, resets the client id and low entropy source. This
-  // should not be called more than once.
-  void CheckForClonedInstall(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
-
-  // Returns the preferred entropy provider used to seed persistent activities
-  // based on whether or not metrics reporting is permitted on this client.
-  //
-  // If metrics reporting is enabled, this method returns an entropy provider
-  // that has a high source of entropy, partially based on the client ID.
-  // Otherwise, it returns an entropy provider that is based on a low entropy
-  // source.
-  scoped_ptr<const base::FieldTrial::EntropyProvider> CreateEntropyProvider();
-
-  // Creates the MetricsStateManager, enforcing that only a single instance
-  // of the class exists at a time. Returns NULL if an instance exists already.
-  static scoped_ptr<MetricsStateManager> Create(
-      PrefService* local_state,
-      const base::Callback<bool(void)>& is_reporting_enabled_callback);
-
-  // Registers local state prefs used by this class.
-  static void RegisterPrefs(PrefRegistrySimple* registry);
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(MetricsStateManagerTest, EntropySourceUsed_Low);
-  FRIEND_TEST_ALL_PREFIXES(MetricsStateManagerTest, EntropySourceUsed_High);
-  FRIEND_TEST_ALL_PREFIXES(MetricsStateManagerTest, LowEntropySource0NotReset);
-  FRIEND_TEST_ALL_PREFIXES(MetricsStateManagerTest,
-                           PermutedEntropyCacheClearedWhenLowEntropyReset);
-  FRIEND_TEST_ALL_PREFIXES(MetricsStateManagerTest, ResetMetricsIDs);
-
-  // Designates which entropy source was returned from this class.
-  // This is used for testing to validate that we return the correct source
-  // depending on the state of the service.
-  enum EntropySourceType {
-    ENTROPY_SOURCE_NONE,
-    ENTROPY_SOURCE_LOW,
-    ENTROPY_SOURCE_HIGH,
-  };
-
-  // Creates the MetricsStateManager with the given |local_state|. Calls
-  // |is_reporting_enabled_callback| to query whether metrics reporting is
-  // enabled. Clients should instead use Create(), which enforces a single
-  // instance of this class is alive at any given time.
-  MetricsStateManager(
-      PrefService* local_state,
-      const base::Callback<bool(void)>& is_reporting_enabled_callback);
-
-  // Returns the low entropy source for this client. This is a random value
-  // that is non-identifying amongst browser clients. This method will
-  // generate the entropy source value if it has not been called before.
-  int GetLowEntropySource();
-
-  // Returns the first entropy source that was returned by this service since
-  // start up, or NONE if neither was returned yet. This is exposed for testing
-  // only.
-  EntropySourceType entropy_source_returned() const {
-    return entropy_source_returned_;
-  }
-
-  // Reset the client id and low entropy source if the kMetricsResetMetricIDs
-  // pref is true.
-  void ResetMetricsIDsIfNecessary();
-
-  // Whether an instance of this class exists. Used to enforce that there aren't
-  // multiple instances of this class at a given time.
-  static bool instance_exists_;
-
-  // Weak pointer to the local state prefs store.
-  PrefService* const local_state_;
-
-  const base::Callback<bool(void)> is_reporting_enabled_callback_;
-
-  // The identifier that's sent to the server with the log reports.
-  std::string client_id_;
-
-  // The non-identifying low entropy source value.
-  int low_entropy_source_;
-
-  // The last entropy source returned by this service, used for testing.
-  EntropySourceType entropy_source_returned_;
-
-  scoped_ptr<ClonedInstallDetector> cloned_install_detector_;
-
-  DISALLOW_COPY_AND_ASSIGN(MetricsStateManager);
-};
-
-}  // namespace metrics
-
-#endif  // CHROME_BROWSER_METRICS_METRICS_STATE_MANAGER_H_