Fix StatisticsRecorder to handle re-entry during tests.

base/metrics/statistics_recorder_unittest.cc

 // Copyright (c) 2012 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/statistics_recorder.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <vector>
@@ skipping 18 matching lines @@
     // registered).
     InitializeStatisticsRecorder();
   }
 
   void TearDown() override {
     UninitializeStatisticsRecorder();
     GlobalHistogramAllocator::ReleaseForTesting();
   }
 
   void InitializeStatisticsRecorder() {
-    statistics_recorder_ = new StatisticsRecorder();
+    DCHECK(!statistics_recorder_);
+    StatisticsRecorder::UninitializeForTesting();
+    statistics_recorder_.reset(new StatisticsRecorder());
   }
 
   void UninitializeStatisticsRecorder() {
-    delete statistics_recorder_;
-    statistics_recorder_ = NULL;
+    statistics_recorder_.reset();
+    StatisticsRecorder::UninitializeForTesting();
   }
 
   Histogram* CreateHistogram(const std::string& name,
                              HistogramBase::Sample min,
                              HistogramBase::Sample max,
                              size_t bucket_count) {
     BucketRanges* ranges = new BucketRanges(bucket_count + 1);
     Histogram::InitializeBucketRanges(min, max, ranges);
     const BucketRanges* registered_ranges =
         StatisticsRecorder::RegisterOrDeleteDuplicateRanges(ranges);
     return new Histogram(name, min, max, registered_ranges);
   }
 
   void DeleteHistogram(HistogramBase* histogram) {
     delete histogram;
   }
 
-  StatisticsRecorder* statistics_recorder_;
+  std::unique_ptr<StatisticsRecorder> statistics_recorder_;
 };
 
 TEST_F(StatisticsRecorderTest, NotInitialized) {
   UninitializeStatisticsRecorder();
 
   ASSERT_FALSE(StatisticsRecorder::IsActive());
 
   StatisticsRecorder::Histograms registered_histograms;
   std::vector<const BucketRanges*> registered_ranges;
 
@@ skipping 434 matching lines @@
   HistogramBase* histogram = Histogram::FactoryGet("TestHistogram", 1, 1000, 10,
                                                    HistogramBase::kNoFlags);
   EXPECT_TRUE(histogram);
   histogram->Add(1);
 
   EXPECT_TRUE(callback_wrapper.called);
   EXPECT_EQ(callback_wrapper.last_histogram_value, 1);
 }
 
 }  // namespace base