Update from https://crrev.com/314320

base/metrics/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.
 
 // Histogram is an object that aggregates statistics, and can summarize them in
 // various forms, including ASCII graphical, HTML, and numerically (as a
 // vector of numbers corresponding to each of the aggregating buckets).
 // See header file for details and examples.
 
 #include "base/metrics/histogram.h"
@@ skipping 351 matching lines @@
   if (!ValidateRangeChecksum(*histogram, range_checksum)) {
     // The serialized histogram might be corrupted.
     return NULL;
   }
   return histogram;
 }
 
 scoped_ptr<SampleVector> Histogram::SnapshotSampleVector() const {
   scoped_ptr<SampleVector> samples(new SampleVector(bucket_ranges()));
   samples->Add(*samples_);
-  return samples;
+  return samples.Pass();
 }
 
 void Histogram::WriteAsciiImpl(bool graph_it,
                                const string& newline,
                                string* output) const {
   // Get local (stack) copies of all effectively volatile class data so that we
   // are consistent across our output activities.
   scoped_ptr<SampleVector> snapshot = SnapshotSampleVector();
   Count sample_count = snapshot->TotalCount();
 
@@ skipping 105 matching lines @@
 }
 
 void Histogram::GetCountAndBucketData(Count* count,
                                       int64* sum,
                                       ListValue* buckets) const {
   scoped_ptr<SampleVector> snapshot = SnapshotSampleVector();
   *count = snapshot->TotalCount();
   *sum = snapshot->sum();
   size_t index = 0;
   for (size_t i = 0; i < bucket_count(); ++i) {
-    Sample count = snapshot->GetCountAtIndex(i);
-    if (count > 0) {
+    Sample count_at_index = snapshot->GetCountAtIndex(i);
+    if (count_at_index > 0) {
       scoped_ptr<DictionaryValue> bucket_value(new DictionaryValue());
       bucket_value->SetInteger("low", ranges(i));
       if (i != bucket_count() - 1)
         bucket_value->SetInteger("high", ranges(i + 1));
-      bucket_value->SetInteger("count", count);
+      bucket_value->SetInteger("count", count_at_index);
       buckets->Set(index, bucket_value.release());
       ++index;
     }
   }
 }
 
 //------------------------------------------------------------------------------
 // LinearHistogram: This histogram uses a traditional set of evenly spaced
 // buckets.
 //------------------------------------------------------------------------------
@@ skipping 322 matching lines @@
 
   BucketRanges* bucket_ranges = new BucketRanges(ranges.size());
   for (size_t i = 0; i < ranges.size(); i++) {
     bucket_ranges->set_range(i, ranges[i]);
   }
   bucket_ranges->ResetChecksum();
   return bucket_ranges;
 }
 
 }  // namespace base