Resetting metrics ids on clump detection.

chrome/browser/metrics/metrics_service.h

 // Copyright (c) 2012 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 CHROME_BROWSER_METRICS_METRICS_SERVICE_H_
 #define CHROME_BROWSER_METRICS_METRICS_SERVICE_H_
 
@@ skipping 350 matching lines @@
   // 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
   // his/her 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);
 
+  // Reset the client id and low entropy source if the kMetricsResetMetricIDs
+  // pref is true.
+  void ResetMetricsIDsIfNecessary();
+
   // 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.
   EntropySourceReturned entropy_source_returned() const {
     return entropy_source_returned_;
@@ skipping 135 matching lines @@
 
   // Returns a list of synthetic field trials that were active for the entire
   // duration of the current log.
   void GetCurrentSyntheticFieldTrials(
       std::vector<chrome_variations::ActiveGroupId>* synthetic_trials);
 
   base::ActionCallback action_callback_;
 
   content::NotificationRegistrar registrar_;
 
+  // Set to true when the client id and low entropy source have been reset due
+  // to the kMetricsResetIds pref being true. This prevents multiple resets

[Alexei Svitkine (slow), 2014/03/28 19:49:02]

This comment isn't correct. It's also set to true if the check was performed and
nothing was reset.

[jwd, 2014/03/28 19:58:58]

Done.

+  // within the same chrome session.
+  bool metrics_ids_reset_check_performed_;
+
   // Indicate whether recording and reporting are currently happening.
   // These should not be set directly, but by calling SetRecording and
   // SetReporting.
   bool recording_active_;
   bool reporting_active_;
 
   // 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_;
 
@@ skipping 96 matching lines @@
   SyntheticTrialGroups synthetic_trial_groups_;
 
   scoped_ptr<metrics::ClonedInstallDetector> cloned_install_detector_;
 
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, ClientIdCorrectlyFormatted);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, IsPluginProcess);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, LowEntropySource0NotReset);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest,
                            PermutedEntropyCacheClearedWhenLowEntropyReset);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, RegisterSyntheticTrial);
+  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, ResetMetricsIDs);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceBrowserTest,
                            CheckLowEntropySourceUsed);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceReportingTest,
                            CheckHighEntropySourceUsed);
 
   DISALLOW_COPY_AND_ASSIGN(MetricsService);
 };
 
 // This class limits and documents access to the IsMetricsReportingEnabled() and
 // IsCrashReportingEnabled() methods. Since these methods are private, each user
@@ skipping 16 matching lines @@
 
   // Returns true if crash reporting is enabled.  This is set at the platform
   // level for Android and ChromeOS, and otherwise is the same as
   // IsMetricsReportingEnabled for desktop Chrome.
   static bool IsCrashReportingEnabled();
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(MetricsServiceHelper);
 };
 
 #endif  // CHROME_BROWSER_METRICS_METRICS_SERVICE_H_