Convert //ash from scoped_ptr to std::unique_ptr

ash/metrics/task_switch_time_tracker_unittest.cc

Index: ash/metrics/task_switch_time_tracker_unittest.cc
diff --git a/ash/metrics/task_switch_time_tracker_unittest.cc b/ash/metrics/task_switch_time_tracker_unittest.cc
index 7fc3aba928305447e5c9890ff9d23fb537efbdff..70b26b9316fec50e7e9ee45504c7ffdb4696e691 100644
--- a/ash/metrics/task_switch_time_tracker_unittest.cc
+++ b/ash/metrics/task_switch_time_tracker_unittest.cc
@@ -37,10 +37,10 @@ class TaskSwitchTimeTrackerTest : public testing::Test {
 
  protected:
   // Used to verify recorded histogram data.
-  scoped_ptr<base::HistogramTester> histogram_tester_;
+  std::unique_ptr<base::HistogramTester> histogram_tester_;
 
   // A Test API that wraps the test target.
-  scoped_ptr<test::TaskSwitchTimeTrackerTestAPI> time_tracker_test_api_;
+  std::unique_ptr<test::TaskSwitchTimeTrackerTestAPI> time_tracker_test_api_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TaskSwitchTimeTrackerTest);