Fix StatisticsRecorder to handle re-entry during tests.

base/metrics/histogram_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/histogram.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 37 matching lines @@
   void TearDown() override {
     if (allocator_) {
       ASSERT_FALSE(allocator_->IsFull());
       ASSERT_FALSE(allocator_->IsCorrupt());
     }
     UninitializeStatisticsRecorder();
     DestroyPersistentHistogramAllocator();
   }
 
   void InitializeStatisticsRecorder() {
-    StatisticsRecorder::ResetForTesting();
-    statistics_recorder_ = new StatisticsRecorder();
+    DCHECK(!statistics_recorder_);
+    statistics_recorder_.reset(new StatisticsRecorder());
   }
 
   void UninitializeStatisticsRecorder() {
-    delete statistics_recorder_;
-    statistics_recorder_ = NULL;
+    statistics_recorder_.reset();
   }
 
   void CreatePersistentHistogramAllocator() {
     // By getting the results-histogram before any persistent allocator
     // is attached, that histogram is guaranteed not to be stored in
     // any persistent memory segment (which simplifies some tests).
     GlobalHistogramAllocator::GetCreateHistogramResultHistogram();
 
     GlobalHistogramAllocator::CreateWithLocalMemory(
         kAllocatorMemorySize, 0, "HistogramAllocatorTest");
     allocator_ = GlobalHistogramAllocator::Get()->memory_allocator();
   }
 
   void DestroyPersistentHistogramAllocator() {
     allocator_ = nullptr;
     GlobalHistogramAllocator::ReleaseForTesting();
   }
 
   const bool use_persistent_histogram_allocator_;
 
-  StatisticsRecorder* statistics_recorder_ = nullptr;
+  std::unique_ptr<StatisticsRecorder> statistics_recorder_;
   std::unique_ptr<char[]> allocator_memory_;
   PersistentMemoryAllocator* allocator_ = nullptr;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HistogramTest);
 };
 
 // Run all HistogramTest cases with both heap and persistent memory.
 INSTANTIATE_TEST_CASE_P(HeapAndPersistent, HistogramTest, testing::Bool());
 
 
 // Check for basic syntax and use.
 TEST_P(HistogramTest, BasicTest) {
   // Try basic construction
   HistogramBase* histogram = Histogram::FactoryGet(
       "TestHistogram", 1, 1000, 10, HistogramBase::kNoFlags);
   EXPECT_TRUE(histogram);
 
   HistogramBase* linear_histogram = LinearHistogram::FactoryGet(
       "TestLinearHistogram", 1, 1000, 10, HistogramBase::kNoFlags);
   EXPECT_TRUE(linear_histogram);
 
   std::vector<int> custom_ranges;
   custom_ranges.push_back(1);
   custom_ranges.push_back(5);
   HistogramBase* custom_histogram = CustomHistogram::FactoryGet(
       "TestCustomHistogram", custom_ranges, HistogramBase::kNoFlags);
   EXPECT_TRUE(custom_histogram);
 
+  // Macros that create hitograms have an internal static variable which will
+  // continue to point to those from the very first run of this method even
+  // during subsequent runs.
+  static bool already_run = false;
+  if (already_run)
+    return;
+  already_run = true;
+
   // Use standard macros (but with fixed samples)
   LOCAL_HISTOGRAM_TIMES("Test2Histogram", TimeDelta::FromDays(1));
   LOCAL_HISTOGRAM_COUNTS("Test3Histogram", 30);
 
   LOCAL_HISTOGRAM_ENUMERATION("Test6Histogram", 129, 130);
 }
 
 // Check that the macro correctly matches histograms by name and records their
 // data together.
 TEST_P(HistogramTest, NameMatchTest) {
@@ skipping 304 matching lines @@
     power_of_2 *= 2;
   }
 
   // Check to see that the bucket counts reflect our additions.
   std::unique_ptr<SampleVector> samples = histogram->SnapshotSampleVector();
   for (int i = 0; i < 8; i++)
     EXPECT_EQ(i + 1, samples->GetCountAtIndex(i));
 }
 
 TEST_P(HistogramTest, CorruptSampleCounts) {
+  // The internal code creates histograms via macros and thus keeps static
+  // pointers to them. If those pointers are to persistent memory which will
+  // be free'd then any following calls to that code will crash with a
+  // segmentation violation.
+  if (use_persistent_histogram_allocator_)
+    return;
+
   Histogram* histogram = static_cast<Histogram*>(
       Histogram::FactoryGet("Histogram", 1, 64, 8, HistogramBase::kNoFlags));
 
   // Add some samples.
   histogram->Add(20);
   histogram->Add(40);
 
   std::unique_ptr<SampleVector> snapshot = histogram->SnapshotSampleVector();
   EXPECT_EQ(HistogramBase::NO_INCONSISTENCIES,
             histogram->FindCorruption(*snapshot));
@@ skipping 253 matching lines @@
   // CustomHistogram needs at least 1 valid range.
   custom_ranges.clear();
   custom_ranges.push_back(0);
   EXPECT_DEATH(CustomHistogram::FactoryGet("BadRangesCustom3", custom_ranges,
                                            HistogramBase::kNoFlags),
                "");
 }
 #endif
 
 }  // namespace base