Standardize usage of virtual/override/final in components/

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 5263a01e2499a35895666b42a07a72b44ffd4daf..eae44f3cf4dc36a02c66fd1dbf90d0421f4853ec 100644
--- a/components/metrics/metrics_service.h
+++ b/components/metrics/metrics_service.h
@@ -98,7 +98,7 @@ class MetricsService : public base::HistogramFlattener {
   MetricsService(MetricsStateManager* state_manager,
                  MetricsServiceClient* client,
                  PrefService* local_state);
-  virtual ~MetricsService();
+  ~MetricsService() override;
 
   // Initializes metrics recording state. Updates various bookkeeping values in
   // prefs and sets up the scheduler. This is a separate function rather than
@@ -152,13 +152,13 @@ class MetricsService : public base::HistogramFlattener {
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
   // HistogramFlattener:
-  virtual void RecordDelta(const base::HistogramBase& histogram,
-                           const base::HistogramSamples& snapshot) override;
-  virtual void InconsistencyDetected(
+  void RecordDelta(const base::HistogramBase& histogram,
+                   const base::HistogramSamples& snapshot) override;
+  void InconsistencyDetected(
       base::HistogramBase::Inconsistency problem) override;
-  virtual void UniqueInconsistencyDetected(
+  void UniqueInconsistencyDetected(
       base::HistogramBase::Inconsistency problem) override;
-  virtual void InconsistencyDetectedInLoggedCount(int amount) override;
+  void InconsistencyDetectedInLoggedCount(int amount) override;
 
   // This should be called when the application is not idle, i.e. the user seems
   // to be interacting with the application.