Implement UMA log throttling for cellular connections

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 <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.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/time/time.h"
 #include "build/build_config.h"
 #include "components/metrics/clean_exit_beacon.h"
+#include "components/metrics/data_use_tracker.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_log_manager.h"
 #include "components/metrics/metrics_provider.h"
 #include "components/metrics/net/network_metrics_provider.h"
 #include "components/variations/synthetic_trials.h"
 
 class PrefService;
 class PrefRegistrySimple;
 
 namespace base {
@@ skipping 33 matching lines @@
     SHUTDOWN_COMPLETE = 700,
   };
 
   // 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);
+
+  // Creates the MetricsService as above with given |cellular_callback|

[Alexei Svitkine (slow), 2016/03/31 20:00:40]

Instead of having a callback as a ctor param, can't it just be a function of the
client interface? Isn't it already?

[gayane -on leave until 09-2017, 2016/03/31 21:55:10]

I think we tried to do this once and I think metrics service cannot depend on
client.

[Alexei Svitkine (slow), 2016/03/31 22:18:02]

I think it should work. MetricsService already depends on client for a number of
other things (e.g. client->GetRegistryBackupKey() right in its ctor).

+  MetricsService(MetricsStateManager* state_manager,
+                 MetricsServiceClient* client,
+                 PrefService* local_state,
+                 base::Callback<void(bool*)> cellular_callback);
   ~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
@@ skipping 114 matching lines @@
   // should not be called more than once.
   void CheckForClonedInstall(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner);
 
   // 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);
 
+  // Returns a callback to data use pref updating function attached to
+  // |data_use_tracker| weak pointer. Should be called on UI thread.

[Alexei Svitkine (slow), 2016/03/31 20:00:40]

This description reads like implementation detail. Can you instead talk about
the purpose of this. Also, mention that the callback should be safe to use from
any thread (don't just say its only for UI thread), although this function
should be called on UI thread.

[gayane -on leave until 09-2017, 2016/03/31 21:55:10]

Done.

+  UpdateUsagePrefCallbackType GetDataUseForwardingCallback();
+
  protected:
   // Exposed for testing.
   MetricsLogManager* log_manager() { return &log_manager_; }
 
  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 {
@@ skipping 234 matching lines @@
   // 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_;
 
   // Execution phase the browser is in.
   static ExecutionPhase execution_phase_;
 
-  // Reduntant marker to check that we completed our shutdown, and set the
+  // 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);
 
+  // Assigns true to output param if current connection type is cellular and
+  // user is assigned to experimental group for enabled cellular uploads.
+  base::Callback<void(bool*)> cellular_callback_;
+
+  // Pointer used for obtaining data use pref updater callback on above layers.
+  scoped_ptr<DataUseTracker> data_use_tracker_;
+
   // 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_;
 
   // Weak pointers factory used for saving state. All weak pointers managed by
   // this factory are invalidated in ScheduleNextStateSave.
   base::WeakPtrFactory<MetricsService> state_saver_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsService);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_METRICS_SERVICE_H_