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

base/metrics/histogram_unittest.cc

Index: base/metrics/histogram_unittest.cc
diff --git a/base/metrics/histogram_unittest.cc b/base/metrics/histogram_unittest.cc
index 784aaeb45a8ce0b0f70313fb380530a7514e20fd..70ce441a8b6d35ea11bdf1d4582ec9615f0c6a89 100644
--- a/base/metrics/histogram_unittest.cc
+++ b/base/metrics/histogram_unittest.cc
@@ -40,10 +40,6 @@ class HistogramTest : public testing::Test {
     // 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 {
@@ -62,10 +58,14 @@ class HistogramTest : public testing::Test {
   }
 
   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(
@@ -76,7 +76,7 @@ class HistogramTest : public testing::Test {
 
   void DestroyPersistentMemoryAllocator() {
     allocator_ = nullptr;
-    SetPersistentHistogramMemoryAllocator(nullptr);
+    delete ReleasePersistentHistogramMemoryAllocatorForTesting();
   }
 
   StatisticsRecorder* statistics_recorder_;