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

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 <stddef.h>
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/json/json_reader.h"
@@ skipping 13 matching lines @@
     // Get this first so it never gets created in persistent storage and will
     // not appear in the StatisticsRecorder after it is re-initialized.
     GetCreateHistogramResultHistogram();
     // Each test will have a clean state (no Histogram / BucketRanges
     // registered).
     InitializeStatisticsRecorder();
   }
 
   void TearDown() override {
     UninitializeStatisticsRecorder();
-    SetPersistentHistogramMemoryAllocator(nullptr);
+    delete ReleasePersistentHistogramMemoryAllocatorForTesting();
   }
 
   void InitializeStatisticsRecorder() {
     statistics_recorder_ = new StatisticsRecorder();
   }
 
   void UninitializeStatisticsRecorder() {
     delete statistics_recorder_;
     statistics_recorder_ = NULL;
   }
@@ skipping 462 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