replace 'virtual ... OVERRIDE' with '... override'

base/metrics/histogram_delta_serialization.h

Index: base/metrics/histogram_delta_serialization.h
diff --git a/base/metrics/histogram_delta_serialization.h b/base/metrics/histogram_delta_serialization.h
index ccadb12894fc57ab57439b00e08560dc2cf02d63..a3c04157c160d8db6dee24880eb8dd538595e48f 100644
--- a/base/metrics/histogram_delta_serialization.h
+++ b/base/metrics/histogram_delta_serialization.h
@@ -38,13 +38,13 @@ class BASE_EXPORT HistogramDeltaSerialization : public HistogramFlattener {
 
  private:
   // HistogramFlattener implementation.
-  virtual void RecordDelta(const HistogramBase& histogram,
-                           const HistogramSamples& snapshot) OVERRIDE;
+  void RecordDelta(const HistogramBase& histogram,
+                   const HistogramSamples& snapshot) override;
   virtual void InconsistencyDetected(
-      HistogramBase::Inconsistency problem) OVERRIDE;
-  virtual void UniqueInconsistencyDetected(
-      HistogramBase::Inconsistency problem) OVERRIDE;
-  virtual void InconsistencyDetectedInLoggedCount(int amount) OVERRIDE;
+      HistogramBase::Inconsistency problem) override;
+  void UniqueInconsistencyDetected(
+      HistogramBase::Inconsistency problem) override;
+  void InconsistencyDetectedInLoggedCount(int amount) override;
 
   // Calculates deltas in histogram counters.
   HistogramSnapshotManager histogram_snapshot_manager_;