Persist setup metrics and have Chrome report them during UMA upload.

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 22 matching lines @@
   HistogramTest() {}
   ~HistogramTest() override {}
 
  protected:
   const int32_t kAllocatorMemorySize = 64 << 10;  // 64 KiB
 
   void SetUp() override {
     // Each test will have a clean state (no Histogram / BucketRanges
     // registered).
     InitializeStatisticsRecorder();
-    // 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).
-    GetCreateHistogramResultHistogram();
   }
 
   void TearDown() override {
     UninitializeStatisticsRecorder();
     DestroyPersistentMemoryAllocator();
   }
 
   void InitializeStatisticsRecorder() {
     StatisticsRecorder::ResetForTesting();
     statistics_recorder_ = new StatisticsRecorder();
   }
 
   void UninitializeStatisticsRecorder() {
     delete statistics_recorder_;
     statistics_recorder_ = NULL;
   }
 
   void CreatePersistentMemoryAllocator() {
+    // 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).
+    GetCreateHistogramResultHistogram();
+
     if (!allocator_memory_)
       allocator_memory_.reset(new char[kAllocatorMemorySize]);
 
-    SetPersistentHistogramMemoryAllocator(nullptr);
     memset(allocator_memory_.get(), 0, kAllocatorMemorySize);
     SetPersistentHistogramMemoryAllocator(
         new PersistentMemoryAllocator(
             allocator_memory_.get(), kAllocatorMemorySize, 0,
             0, "HistogramAllocatorTest", false));
     allocator_ = GetPersistentHistogramMemoryAllocator();
   }
 
   void DestroyPersistentMemoryAllocator() {
     allocator_ = nullptr;
-    SetPersistentHistogramMemoryAllocator(nullptr);
+    delete ReleasePersistentHistogramMemoryAllocatorForTesting();
   }
 
   StatisticsRecorder* statistics_recorder_;
   scoped_ptr<char[]> allocator_memory_;
   PersistentMemoryAllocator* allocator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HistogramTest);
 };
 
@@ skipping 681 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