Remove typically unused local_metadata_ field.

base/metrics/sample_map.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/sample_map.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/stl_util.h"
@@ skipping 61 matching lines @@
 void SampleMapIterator::SkipEmptyBuckets() {
   while (!Done() && iter_->second == 0) {
     ++iter_;
   }
 }
 
 }  // namespace
 
 SampleMap::SampleMap() : SampleMap(0) {}
 
-SampleMap::SampleMap(uint64_t id) : HistogramSamples(id) {}
+SampleMap::SampleMap(uint64_t id) : HistogramSamples(id, new LocalMetadata()) {}
 
-SampleMap::~SampleMap() {}
+SampleMap::~SampleMap() {
+  delete static_cast<LocalMetadata*>(meta());
+}
 
 void SampleMap::Accumulate(Sample value, Count count) {
   sample_counts_[value] += count;
   IncreaseSumAndCount(strict_cast<int64_t>(count) * value, count);
 }
 
 Count SampleMap::GetCount(Sample value) const {
   std::map<Sample, Count>::const_iterator it = sample_counts_.find(value);
   if (it == sample_counts_.end())
     return 0;
@@ skipping 20 matching lines @@
     iter->Get(&min, &max, &count);
     if (strict_cast<int64_t>(min) + 1 != max)
       return false;  // SparseHistogram only supports bucket with size 1.
 
     sample_counts_[min] += (op == HistogramSamples::ADD) ? count : -count;
   }
   return true;
 }
 
 }  // namespace base