Remove MetricsServiceObserver in favor of MetricsProvider.

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 <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.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/strings/string16.h"
-#include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_log_manager.h"
 #include "components/metrics/metrics_provider.h"
-#include "components/metrics/metrics_service_observer.h"
 #include "components/variations/active_field_trials.h"
 
 class MetricsServiceAccessor;
 class PrefService;
 class PrefRegistrySimple;
 
 namespace base {
 class DictionaryValue;
 class HistogramSamples;
 class MessageLoopProxy;
@@ skipping 234 matching lines @@
 
   // 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();
 
-  // Registers/unregisters |observer| to receive MetricsLog notifications.
-  void AddObserver(MetricsServiceObserver* observer);
-  void RemoveObserver(MetricsServiceObserver* observer);
+  // Notifies providers when a new metrics log is created.
   void NotifyOnDidCreateMetricsLog();
 
   // Schedule the next save of LocalState information.  This is called
   // automatically by the task that performs each save to schedule the next one.
   void ScheduleNextStateSave();
 
   // Save the LocalState information immediately. This should not be called by
   // anybody other than the scheduler to avoid doing too many writes. When you
   // make a change, call ScheduleNextStateSave() instead.
   void SaveLocalState();
@@ skipping 140 matching lines @@
 
   // The scheduler for determining when uploads should happen.
   scoped_ptr<MetricsReportingScheduler> 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_;
+
   // Execution phase the browser is in.
   static ExecutionPhase execution_phase_;
 
   // Reduntant marker to check that we completed our shutdown, and set the
   // exited-cleanly bit in the prefs.
   static ShutdownCleanliness clean_shutdown_status_;
 
-  // Field trial groups that map to Chrome configuration states.
-  SyntheticTrialGroups synthetic_trial_groups_;
-
-  ObserverList<MetricsServiceObserver> observers_;
-
-  // Confirms single-threaded access to |observers_| in debug builds.
-  base::ThreadChecker thread_checker_;
-
   friend class ::MetricsServiceAccessor;
 
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, IsPluginProcess);
-  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, MetricsServiceObserver);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest,
                            PermutedEntropyCacheClearedWhenLowEntropyReset);
   FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, RegisterSyntheticTrial);
 
   DISALLOW_COPY_AND_ASSIGN(MetricsService);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_METRICS_SERVICE_H_