Add ownership-transfer to histogram management calls.

base/metrics/sparse_histogram.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 "base/metrics/sparse_histogram.h"
 
 #include <utility>
 
 #include "base/metrics/metrics_hashes.h"
 #include "base/metrics/sample_map.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/pickle.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/lock.h"
 
 namespace base {
 
 typedef HistogramBase::Count Count;
 typedef HistogramBase::Sample Sample;
 
 // static
 HistogramBase* SparseHistogram::FactoryGet(const std::string& name,
                                            int32_t flags) {
   HistogramBase* histogram = StatisticsRecorder::FindHistogram(name);
 
   if (!histogram) {
     // To avoid racy destruction at shutdown, the following will be leaked.
-    HistogramBase* tentative_histogram = new SparseHistogram(name);
+    scoped_ptr<HistogramBase> tentative_histogram(new SparseHistogram(name));
     tentative_histogram->SetFlags(flags);
-    histogram =
-        StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram);
+    histogram = StatisticsRecorder::RegisterOrDeleteDuplicate(
+        std::move(tentative_histogram));
   }
   DCHECK_EQ(SPARSE_HISTOGRAM, histogram->GetHistogramType());
   return histogram;
 }
 
 SparseHistogram::~SparseHistogram() {}
 
 uint64_t SparseHistogram::name_hash() const {
   return samples_.id();
 }
@@ skipping 155 matching lines @@
                                        std::string* output) const {
   StringAppendF(output,
                 "Histogram: %s recorded %d samples",
                 histogram_name().c_str(),
                 total_count);
   if (flags() & ~kHexRangePrintingFlag)
     StringAppendF(output, " (flags = 0x%x)", flags() & ~kHexRangePrintingFlag);
 }
 
 }  // namespace base