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();
   }
 
   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();
+  StatisticsRecorder::UninitializeForTesting();

[Alexei Svitkine (slow), 2016/04/08 15:04:19]

Shouldn't this be part of UninitializeStatisticsRecorder()?

[bcwhite, 2016/04/08 16:06:33]

It's not generally important since it's just a stack of SRs now.  This test,
however, specifically tests the functionality when that stack is empty so it was
necessary.

Can't see any harm in doing it all the time, though, so Done.

 
   ASSERT_FALSE(StatisticsRecorder::IsActive());
 
   StatisticsRecorder::Histograms registered_histograms;
   std::vector<const BucketRanges*> registered_ranges;
 
   StatisticsRecorder::GetHistograms(&registered_histograms);
   EXPECT_EQ(0u, registered_histograms.size());
 
   Histogram* histogram = CreateHistogram("TestHistogram", 1, 1000, 10);
@@ skipping 430 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