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

chrome/browser/ui/webui/performance_monitor/performance_monitor_ui_util_unittest.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 <string>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/time.h"
 #include "chrome/browser/performance_monitor/metric.h"
 #include "chrome/browser/ui/webui/performance_monitor/performance_monitor_ui_util.h"
@@ skipping 24 matching lines @@
         aggregator.reset(new NoAggregation());
         break;
       case AGGREGATION_METHOD_MEDIAN:
         aggregator.reset(new MedianAggregation());
         break;
       case AGGREGATION_METHOD_MEAN:
         aggregator.reset(new MeanAggregation());
         break;
       default:
         NOTREACHED();
-        return scoped_ptr<Database::MetricVector>(NULL);
+        return scoped_ptr<Database::MetricVector>();
     }
     return aggregator->AggregateInterval(
         type, &metric, metrics->end(), start, kMaxTime, resolution);
   }
 };
 
 TEST_F(PerformanceMonitorUtilTest, AggregateMetricEmptyTest) {
   Database::MetricVector metric_vector;
   const base::Time data_time = base::Time::FromDoubleT(1);
   metric_vector.push_back(Metric(METRIC_CPU_USAGE, data_time, 1));
@@ skipping 187 matching lines @@
   expected = 12;
   for (Database::MetricVector::const_iterator iter = metric_series.begin();
        iter != metric_series.end(); ++iter) {
     EXPECT_EQ(expected, iter->value);
     EXPECT_EQ(base::Time::FromDoubleT(expected), iter->time);
     ++expected;
   }
 }
 
 }  // namespace performance_monitor