Revert of Add support for single sample metrics.

components/metrics/single_sample_metrics_factory_impl_unittest.cc

Index: components/metrics/single_sample_metrics_factory_impl_unittest.cc
diff --git a/components/metrics/single_sample_metrics_factory_impl_unittest.cc b/components/metrics/single_sample_metrics_factory_impl_unittest.cc
deleted file mode 100644
index 0ef75be789851849150efcea49c5b78823994600..0000000000000000000000000000000000000000
--- a/components/metrics/single_sample_metrics_factory_impl_unittest.cc
+++ /dev/null
@@ -1,183 +0,0 @@
-// Copyright 2017 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/single_sample_metrics_factory_impl.h"
-
-#include "base/message_loop/message_loop.h"
-#include "base/run_loop.h"
-#include "base/test/gtest_util.h"
-#include "base/test/histogram_tester.h"
-#include "base/threading/thread.h"
-#include "components/metrics/single_sample_metrics.h"
-#include "services/service_manager/public/cpp/bind_source_info.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace metrics {
-
-namespace {
-
-const base::HistogramBase::Sample kMin = 1;
-const base::HistogramBase::Sample kMax = 10;
-const uint32_t kBucketCount = 10;
-const char kMetricName[] = "Single.Sample.Metric";
-
-class SingleSampleMetricsFactoryImplTest : public testing::Test {
- public:
-  SingleSampleMetricsFactoryImplTest() : thread_("TestThread") {
-    InitializeSingleSampleMetricsFactory(
-        base::BindRepeating(&SingleSampleMetricsFactoryImplTest::CreateProvider,
-                            base::Unretained(this)));
-    factory_ = static_cast<SingleSampleMetricsFactoryImpl*>(
-        base::SingleSampleMetricsFactory::Get());
-  }
-
-  ~SingleSampleMetricsFactoryImplTest() override {
-    factory_->DestroyProviderForTesting();
-    if (thread_.IsRunning()) {
-      thread_.task_runner()->PostTask(
-          FROM_HERE,
-          base::Bind(&SingleSampleMetricsFactoryImpl::DestroyProviderForTesting,
-                     base::Unretained(factory_)));
-      thread_.Stop();
-    }
-    base::SingleSampleMetricsFactory::DeleteFactoryForTesting();
-  }
-
- protected:
-  void StartThread() { ASSERT_TRUE(thread_.Start()); }
-
-  void CreateProvider(mojom::SingleSampleMetricsProviderRequest request) {
-    CreateSingleSampleMetricsProvider(service_manager::BindSourceInfo(),
-                                      std::move(request));
-    provider_count_++;
-  }
-
-  std::unique_ptr<base::SingleSampleMetric> CreateMetricOnThread() {
-    std::unique_ptr<base::SingleSampleMetric> metric;
-    base::RunLoop run_loop;
-    thread_.task_runner()->PostTaskAndReply(
-        FROM_HERE,
-        base::Bind(&SingleSampleMetricsFactoryImplTest::CreateAndStoreMetric,
-                   base::Unretained(this), &metric),
-        run_loop.QuitClosure());
-    run_loop.Run();
-    return metric;
-  }
-
-  void CreateAndStoreMetric(std::unique_ptr<base::SingleSampleMetric>* metric) {
-    *metric = factory_->CreateCustomCountsMetric(kMetricName, kMin, kMax,
-                                                 kBucketCount);
-  }
-
-  base::MessageLoop message_looqp_;
-  SingleSampleMetricsFactoryImpl* factory_;
-  base::Thread thread_;
-  size_t provider_count_ = 0;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(SingleSampleMetricsFactoryImplTest);
-};
-
-}  // namespace
-
-TEST_F(SingleSampleMetricsFactoryImplTest, SingleProvider) {
-  std::unique_ptr<base::SingleSampleMetric> metric1 =
-      factory_->CreateCustomCountsMetric(kMetricName, kMin, kMax, kBucketCount);
-
-  std::unique_ptr<base::SingleSampleMetric> metric2 =
-      factory_->CreateCustomCountsMetric(kMetricName, kMin, kMax, kBucketCount);
-
-  // Verify that only a single provider is created for multiple metrics.
-  base::RunLoop().RunUntilIdle();
-  EXPECT_EQ(1u, provider_count_);
-}
-
-TEST_F(SingleSampleMetricsFactoryImplTest, DoesNothing) {
-  base::HistogramTester tester;
-
-  std::unique_ptr<base::SingleSampleMetric> metric =
-      factory_->CreateCustomCountsMetric(kMetricName, kMin, kMax, kBucketCount);
-  metric.reset();
-
-  // Verify that no sample is recorded if SetSample() is never called.
-  base::RunLoop().RunUntilIdle();
-  tester.ExpectTotalCount(kMetricName, 0);
-}
-
-TEST_F(SingleSampleMetricsFactoryImplTest, DefaultSingleSampleMetricWithValue) {
-  base::HistogramTester tester;
-  std::unique_ptr<base::SingleSampleMetric> metric =
-      factory_->CreateCustomCountsMetric(kMetricName, kMin, kMax, kBucketCount);
-
-  const base::HistogramBase::Sample kLastSample = 9;
-  metric->SetSample(1);
-  metric->SetSample(3);
-  metric->SetSample(5);
-  metric->SetSample(kLastSample);
-  metric.reset();
-
-  // Verify only the last sample sent to SetSample() is recorded.
-  base::RunLoop().RunUntilIdle();
-  tester.ExpectUniqueSample(kMetricName, kLastSample, 1);
-
-  // Verify construction implicitly by requesting a histogram with the same
-  // parameters; this test relies on the fact that histogram objects are unique
-  // per name. Different parameters will result in a nullptr being returned.
-  EXPECT_FALSE(base::Histogram::FactoryGet(kMetricName, 1, 3, 3,
-                                           base::HistogramBase::kNoFlags));
-  EXPECT_TRUE(base::Histogram::FactoryGet(
-      kMetricName, kMin, kMax, kBucketCount,
-      base::HistogramBase::kUmaTargetedHistogramFlag));
-}
-
-TEST_F(SingleSampleMetricsFactoryImplTest, MultithreadedMetrics) {
-  base::HistogramTester tester;
-  std::unique_ptr<base::SingleSampleMetric> metric =
-      factory_->CreateCustomCountsMetric(kMetricName, kMin, kMax, kBucketCount);
-  EXPECT_EQ(1u, provider_count_);
-
-  StartThread();
-
-  std::unique_ptr<base::SingleSampleMetric> threaded_metric =
-      CreateMetricOnThread();
-  ASSERT_TRUE(threaded_metric);
-
-  // A second provider should be created to handle requests on our new thread.
-  EXPECT_EQ(2u, provider_count_);
-
-  // Calls from the wrong thread should DCHECK.
-  EXPECT_DCHECK_DEATH(threaded_metric->SetSample(5));
-  EXPECT_DCHECK_DEATH(threaded_metric.reset());
-
-  // Test that samples are set on each thread correctly.
-  const base::HistogramBase::Sample kSample = 7;
-
-  {
-    metric->SetSample(kSample);
-
-    base::RunLoop run_loop;
-    thread_.task_runner()->PostTaskAndReply(
-        FROM_HERE,
-        base::Bind(&base::SingleSampleMetric::SetSample,
-                   base::Unretained(threaded_metric.get()), kSample),
-        run_loop.QuitClosure());
-    run_loop.Run();
-  }
-
-  // Release metrics and cycle threads to ensure destruction completes.
-  {
-    thread_.task_runner()->DeleteSoon(FROM_HERE, threaded_metric.release());
-
-    base::RunLoop run_loop;
-    thread_.task_runner()->PostTaskAndReply(
-        FROM_HERE, base::Bind(&base::DoNothing), run_loop.QuitClosure());
-    run_loop.Run();
-  }
-
-  metric.reset();
-  base::RunLoop().RunUntilIdle();
-  tester.ExpectUniqueSample(kMetricName, kSample, 2);
-}
-
-}  // namespace metrics