Refactor histogram_persistence to be a class.

components/metrics/file_metrics_provider_unittest.cc

 // Copyright 2016 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 "components/metrics/file_metrics_provider.h"
 
 #include "base/files/file_util.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_flattener.h"
-#include "base/metrics/histogram_persistence.h"
 #include "base/metrics/histogram_snapshot_manager.h"
+#include "base/metrics/persistent_histogram_allocator.h"
 #include "base/metrics/persistent_memory_allocator.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/test/test_simple_task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "components/metrics/metrics_pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/testing_pref_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
@@ skipping 72 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(FileMetricsProviderTest);
 };
 
 
 TEST_F(FileMetricsProviderTest, AccessMetrics) {
   ASSERT_FALSE(PathExists(metrics_file()));
 
   {
     // Get this first so it isn't created inside the persistent allocator.
-    base::GetCreateHistogramResultHistogram();
+    base::PersistentHistogramAllocator::GetCreateHistogramResultHistogram();
 
-    base::SetPersistentHistogramMemoryAllocator(
-        new base::LocalPersistentMemoryAllocator(64 << 10, 0, kMetricsName));
+    base::PersistentHistogramAllocator::CreateGlobalAllocatorOnLocalMemory(
+        64 << 10, 0, kMetricsName);
     base::HistogramBase* foo =
         base::Histogram::FactoryGet("foo", 1, 100, 10, 0);
     base::HistogramBase* bar =
         base::Histogram::FactoryGet("bar", 1, 100, 10, 0);
     foo->Add(42);
     bar->Add(84);
 
-    scoped_ptr<base::PersistentMemoryAllocator> allocator(
-        base::ReleasePersistentHistogramMemoryAllocatorForTesting());
+    scoped_ptr<base::PersistentHistogramAllocator> histogram_allocator =
+        base::PersistentHistogramAllocator::ReleaseGlobalAllocatorForTesting();
+    base::PersistentMemoryAllocator* allocator =
+        histogram_allocator->memory_allocator();
     base::File writer(metrics_file(),
                       base::File::FLAG_CREATE | base::File::FLAG_WRITE);
     ASSERT_TRUE(writer.IsValid());
     ASSERT_EQ(static_cast<int>(allocator->used()),
               writer.Write(0, (const char*)allocator->data(),
                            allocator->used()));
   }
 
   // Register the file and allow the "checker" task to run.
   ASSERT_TRUE(PathExists(metrics_file()));
@@ skipping 52 matching lines @@
     HistogramFlattenerDeltaRecorder flattener;
     base::HistogramSnapshotManager snapshot_manager(&flattener);
     snapshot_manager.StartDeltas();
     provider()->RecordHistogramSnapshots(&snapshot_manager);
     snapshot_manager.FinishDeltas();
     EXPECT_EQ(2U, flattener.GetRecordedDeltaHistogramNames().size());
   }
 }
 
 }  // namespace metrics