Refactor VariationsHttpHeaderProvider.

components/metrics/metrics_service.h

Index: components/metrics/metrics_service.h
diff --git a/components/metrics/metrics_service.h b/components/metrics/metrics_service.h
index 234508327238273a11989328dd18d1ef99b617f3..0939c139bd2a17e6dcb7781ab9359d8af6a130b8 100644
--- a/components/metrics/metrics_service.h
+++ b/components/metrics/metrics_service.h
@@ -28,7 +28,7 @@
 #include "components/metrics/metrics_log_manager.h"
 #include "components/metrics/metrics_provider.h"
 #include "components/metrics/net/network_metrics_provider.h"
-#include "components/variations/active_field_trials.h"
+#include "components/variations/synthetic_trials.h"
 
 class PrefService;
 class PrefRegistrySimple;
@@ -55,39 +55,6 @@ class MetricsServiceAccessor;
 class MetricsServiceClient;
 class MetricsStateManager;
 
-// A Field Trial and its selected group, which represent a particular
-// Chrome configuration state. For example, the trial name could map to
-// a preference name, and the group name could map to a preference value.
-struct SyntheticTrialGroup {
- public:
-  ~SyntheticTrialGroup();
-
-  variations::ActiveGroupId id;
-  base::TimeTicks start_time;
-
- private:
-  // Synthetic field trial users:
-  friend class MetricsServiceAccessor;
-  friend class MetricsService;
-  FRIEND_TEST_ALL_PREFIXES(MetricsServiceTest, RegisterSyntheticTrial);
-
-  // This constructor is private specifically so as to control which code is
-  // able to access it. New code that wishes to use it should be added as a
-  // friend class.
-  SyntheticTrialGroup(uint32 trial, uint32 group);
-};
-
-// Interface class to observe changes to synthetic trials in MetricsService.
-class SyntheticTrialObserver {
- public:
-  // Called when the list of synthetic field trial groups has changed.
-  virtual void OnSyntheticTrialsChanged(
-      const std::vector<SyntheticTrialGroup>& groups) = 0;
-
- protected:
-  virtual ~SyntheticTrialObserver() {}
-};
-
 // See metrics_service.cc for a detailed description.
 class MetricsService : public base::HistogramFlattener {
  public:
@@ -216,26 +183,17 @@ class MetricsService : public base::HistogramFlattener {
   // This value should be true when process has completed shutdown.
   static bool UmaMetricsProperlyShutdown();
 
-  // 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
-  // annotated with this trial group if and only if all events in the report
-  // were created after the trial is registered. Only one group name may be
-  // registered at a time for a given trial_name. Only the last group name that
-  // is registered for a given trial name will be recorded. The values passed
-  // in must not correspond to any real field trial in the code.
-  // To use this method, SyntheticTrialGroup should friend your class.
-  void RegisterSyntheticFieldTrial(const SyntheticTrialGroup& trial_group);
-
   // 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);
 
   // Adds an observer to be notified when the synthetic trials list changes.
-  void AddSyntheticTrialObserver(SyntheticTrialObserver* observer);
+  void AddSyntheticTrialObserver(variations::SyntheticTrialObserver* observer);
 
   // Removes an existing observer of synthetic trials list changes.
-  void RemoveSyntheticTrialObserver(SyntheticTrialObserver* observer);
+  void RemoveSyntheticTrialObserver(
+      variations::SyntheticTrialObserver* observer);
 
   // Register the specified |provider| to provide additional metrics into the
   // UMA log. Should be called during MetricsService initialization only.
@@ -258,6 +216,8 @@ class MetricsService : public base::HistogramFlattener {
   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 {
@@ -281,7 +241,17 @@ class MetricsService : public base::HistogramFlattener {
     UNSET
   };
 
-  typedef std::vector<SyntheticTrialGroup> SyntheticTrialGroups;
+  typedef std::vector<variations::SyntheticTrialGroup> SyntheticTrialGroups;
+
+  // 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
+  // annotated with this trial group if and only if all events in the report
+  // were created after the trial is registered. Only one group name may be
+  // registered at a time for a given trial_name. Only the last group name that
+  // is registered for a given trial name will be recorded. The values passed
+  // in must not correspond to any real field trial in the code.
+  void RegisterSyntheticFieldTrial(
+      const variations::SyntheticTrialGroup& trial_group);
 
   // Calls into the client to initialize some system profile metrics.
   void StartInitTask();
@@ -489,7 +459,8 @@ class MetricsService : public base::HistogramFlattener {
   SyntheticTrialGroups synthetic_trial_groups_;
 
   // List of observers of |synthetic_trial_groups_| changes.
-  base::ObserverList<SyntheticTrialObserver> synthetic_trial_observer_list_;
+  base::ObserverList<variations::SyntheticTrialObserver>
+      synthetic_trial_observer_list_;
 
   // Execution phase the browser is in.
   static ExecutionPhase execution_phase_;