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

chrome/browser/performance_monitor/performance_monitor.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/performance_monitor/performance_monitor.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 80 matching lines @@
 }
 
 }  // namespace
 
 bool PerformanceMonitor::initialized_ = false;
 
 PerformanceMonitor::PerformanceDataForIOThread::PerformanceDataForIOThread()
     : network_bytes_read(0) {
 }
 
-PerformanceMonitor::PerformanceMonitor() : database_(NULL),
-                                           metrics_map_(new MetricsMap) {
-}
+PerformanceMonitor::PerformanceMonitor() : metrics_map_(new MetricsMap) {}
 
 PerformanceMonitor::~PerformanceMonitor() {
   BrowserThread::PostBlockingPoolSequencedTask(
       Database::kDatabaseSequenceToken,
       FROM_HERE,
       base::Bind(&DeleteDatabaseOnBackgroundThread, database_.release()));
 }
 
 bool PerformanceMonitor::SetDatabasePath(const base::FilePath& path) {
   if (!database_.get()) {
@@ skipping 530 matching lines @@
     if (!url_list.empty())
       url_list += ", ";
 
     url_list += url;
   }
 
   AddEvent(util::CreateRendererFailureEvent(base::Time::Now(), type, url_list));
 }
 
 }  // namespace performance_monitor