[ObjC ARC] Converts ios/chrome/browser/metrics:unit_tests to ARC.Automatically generated ARCMigra…

ios/chrome/browser/metrics/mobile_session_shutdown_metrics_provider_unittest.mm

 // Copyright 2015 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 "ios/chrome/browser/metrics/mobile_session_shutdown_metrics_provider.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/test/histogram_tester.h"
 #include "base/test/test_simple_task_runner.h"
 #include "components/metrics/metrics_pref_names.h"
 #include "components/metrics/metrics_service.h"
 #include "components/metrics/metrics_state_manager.h"
 #include "components/metrics/test_enabled_state_provider.h"
 #include "components/metrics/test_metrics_service_client.h"
 #include "components/prefs/testing_pref_service.h"
 #include "testing/gtest/include/gtest/gtest-param-test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // An MobileSessionShutdownMetricsProvider that returns fake values for the last
 // session environment query methods.
 class MobileSessionShutdownMetricsProviderForTesting
     : public MobileSessionShutdownMetricsProvider {
  public:
   explicit MobileSessionShutdownMetricsProviderForTesting(
       metrics::MetricsService* metrics_service)
       : MobileSessionShutdownMetricsProvider(metrics_service) {}
 
   void set_is_first_launch_after_upgrade(bool value) {
@@ skipping 139 matching lines @@
   // Now call the method under test and verify exactly one sample is written to
   // the expected bucket.
   metrics_provider_->ProvideInitialStabilityMetrics(nullptr);
   histogram_tester.ExpectUniqueSample("Stability.MobileSessionShutdownType",
                                       expected_buckets[GetParam()], 1);
 }
 
 INSTANTIATE_TEST_CASE_P(/* No InstantiationName */,
                         MobileSessionShutdownMetricsProviderTest,
                         testing::Range(0, 32));