Convert //ash from scoped_ptr to std::unique_ptr

ash/metrics/task_switch_metrics_recorder_unittest.cc

Index: ash/metrics/task_switch_metrics_recorder_unittest.cc
diff --git a/ash/metrics/task_switch_metrics_recorder_unittest.cc b/ash/metrics/task_switch_metrics_recorder_unittest.cc
index 9c24983242d5d5379a816898deb6ea4a2f1e7964..75bbe580c57830c49a3abbc40abf0fdec60699ae 100644
--- a/ash/metrics/task_switch_metrics_recorder_unittest.cc
+++ b/ash/metrics/task_switch_metrics_recorder_unittest.cc
@@ -26,10 +26,10 @@ class TaskSwitchMetricsRecorderTest : public testing::Test {
 
  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);