Rewrite scoped_ptr<T>(NULL) to use the default ctor in chrome/.

chrome/browser/ui/webui/performance_monitor/performance_monitor_ui_util.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/webui/performance_monitor/performance_monitor_ui_util.h"
 
 #include <algorithm>
 
 #include "base/time.h"
 #include "chrome/browser/performance_monitor/metric.h"
@@ skipping 154 matching lines @@
 }
 
 scoped_ptr<VectorOfMetricVectors> AggregateMetric(
     MetricType type,
     const Database::MetricVector* metrics,
     const base::Time& start,
     const std::vector<TimeRange>& intervals,
     const base::TimeDelta& resolution,
     AggregationMethod method) {
   if (!metrics || intervals.empty())
-    return scoped_ptr<VectorOfMetricVectors>(NULL);
+    return scoped_ptr<VectorOfMetricVectors>();
 
   CHECK(resolution > base::TimeDelta());
 
   switch (method) {
     case AGGREGATION_METHOD_NONE:
       return NoAggregation().AggregateMetrics(
           type, metrics, start, intervals, resolution);
     case AGGREGATION_METHOD_MEDIAN:
       return MedianAggregation().AggregateMetrics(
           type, metrics, start, intervals, resolution);
     case AGGREGATION_METHOD_MEAN:
       return MeanAggregation().AggregateMetrics(
           type, metrics, start, intervals, resolution);
     default:
       NOTREACHED();
-      return scoped_ptr<VectorOfMetricVectors>(NULL);
+      return scoped_ptr<VectorOfMetricVectors>();
   }
 }
 
 }  // namespace performance_monitor