Add support for persistent sparse histograms.

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 19 matching lines @@
 // Test parameter indicates if a persistent memory allocator should be used
 // for histogram allocation. False will allocate histograms from the process
 // heap.
 class HistogramTest : public testing::TestWithParam<bool> {
  protected:
   const int32_t kAllocatorMemorySize = 8 << 20;  // 8 MiB
 
   HistogramTest() : use_persistent_histogram_allocator_(GetParam()) {}
 
   void SetUp() override {
+    if (use_persistent_histogram_allocator_)
+      CreatePersistentMemoryAllocator();
+
     // Each test will have a clean state (no Histogram / BucketRanges
     // registered).
     InitializeStatisticsRecorder();
-    if (use_persistent_histogram_allocator_)
-      CreatePersistentMemoryAllocator();
   }
 
   void TearDown() override {
     if (allocator_) {
       ASSERT_FALSE(allocator_->IsFull());
       ASSERT_FALSE(allocator_->IsCorrupt());
     }
     UninitializeStatisticsRecorder();
     DestroyPersistentMemoryAllocator();
   }
@@ skipping 742 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