Convert //ash from scoped_ptr to std::unique_ptr

ash/metrics/task_switch_metrics_recorder_unittest.cc

 // 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 "ash/metrics/task_switch_metrics_recorder.h"
 
 #include "base/test/histogram_tester.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace ash {
 namespace {
 
 // Test fixture for the TaskSwitchMetricsRecorder class.
 class TaskSwitchMetricsRecorderTest : public testing::Test {
  public:
   TaskSwitchMetricsRecorderTest();
   ~TaskSwitchMetricsRecorderTest() override;
 
   // Wrapper to the test targets OnTaskSwitch(TaskSwitchSource) method.
   void OnTaskSwitch(
       TaskSwitchMetricsRecorder::TaskSwitchSource task_switch_source);
 
   // testing::Test:
   void SetUp() override;
   void TearDown() override;
 
  protected:
   // Used to verify recorded data.
-  scoped_ptr<base::HistogramTester> histogram_tester_;
+  std::unique_ptr<base::HistogramTester> histogram_tester_;
 
   // The test target.
-  scoped_ptr<TaskSwitchMetricsRecorder> task_switch_metrics_recorder_;
+  std::unique_ptr<TaskSwitchMetricsRecorder> task_switch_metrics_recorder_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TaskSwitchMetricsRecorderTest);
 };
 
 TaskSwitchMetricsRecorderTest::TaskSwitchMetricsRecorderTest() {
 }
 
 TaskSwitchMetricsRecorderTest::~TaskSwitchMetricsRecorderTest() {
 }
@@ skipping 112 matching lines @@
 
   OnTaskSwitch(TaskSwitchMetricsRecorder::APP_LIST);
   OnTaskSwitch(TaskSwitchMetricsRecorder::APP_LIST);
   histogram_tester_->ExpectTotalCount(kHistogramName, 1);
 
   OnTaskSwitch(TaskSwitchMetricsRecorder::APP_LIST);
   histogram_tester_->ExpectTotalCount(kHistogramName, 2);
 }
 
 }  // namespace ash