Standardize usage of virtual/override/final specifiers in base/.

base/metrics/histogram_snapshot_manager_unittest.cc

 // 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.
 
 #include "base/metrics/histogram_snapshot_manager.h"
 
 #include <string>
 #include <vector>
 
 #include "base/metrics/histogram.h"
@@ skipping 33 matching lines @@
   std::vector<std::string> recorded_delta_histogram_names_;
 
   DISALLOW_COPY_AND_ASSIGN(HistogramFlattenerDeltaRecorder);
 };
 
 class HistogramSnapshotManagerTest : public testing::Test {
  protected:
   HistogramSnapshotManagerTest()
       : histogram_snapshot_manager_(&histogram_flattener_delta_recorder_) {}
 
-  virtual ~HistogramSnapshotManagerTest() {}
+  ~HistogramSnapshotManagerTest() override {}
 
   StatisticsRecorder statistics_recorder_;
   HistogramFlattenerDeltaRecorder histogram_flattener_delta_recorder_;
   HistogramSnapshotManager histogram_snapshot_manager_;
 };
 
 TEST_F(HistogramSnapshotManagerTest, PrepareDeltasNoFlagsFilter) {
   // kNoFlags filter should record all histograms.
   UMA_HISTOGRAM_ENUMERATION("UmaHistogram", 1, 2);
   UMA_STABILITY_HISTOGRAM_ENUMERATION("UmaStabilityHistogram", 1, 2);
@@ skipping 31 matching lines @@
   histogram_snapshot_manager_.PrepareDeltas(
       HistogramBase::kNoFlags, HistogramBase::kUmaStabilityHistogramFlag);
 
   const std::vector<std::string>& histograms =
       histogram_flattener_delta_recorder_.GetRecordedDeltaHistogramNames();
   EXPECT_EQ(1U, histograms.size());
   EXPECT_EQ("UmaStabilityHistogram", histograms[0]);
 }
 
 }  // namespace base