Fix a bunch of IWYU violators that don't include scoped_ptr.h

ash/metrics/task_switch_metrics_recorder.h

 // 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.
 
 #ifndef ASH_METRICS_TASK_SWITCH_METRIC_RECORDER_H_
 #define ASH_METRICS_TASK_SWITCH_METRIC_RECORDER_H_
 
 #include <string>
 
 #include "ash/ash_export.h"
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 
 namespace aura {
 class Window;
 }  // namespace aura
 
 namespace ash {
 
 class TaskSwitchTimeTracker;
 
 // The TaskSwitchMetricsRecorder class records UMA metrics related to task
@@ skipping 64 matching lines @@
   // |histogram_map_| is populated on demand the first time a
   // TaskSwitchTimeTracker is needed for a given source.
   base::ScopedPtrHashMap<int, scoped_ptr<TaskSwitchTimeTracker>> histogram_map_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskSwitchMetricsRecorder);
 };
 
 }  // namespace ash
 
 #endif  // ASH_METRICS_TASK_SWITCH_METRIC_RECORDER_H_