Histogram type support in HistogramBase and remove SetRangeDescription function

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 "base/metrics/sample_map.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/synchronization/lock.h"
 
 using std::map;
 using std::string;
 
 namespace base {
 
 typedef HistogramBase::Count Count;
 typedef HistogramBase::Sample Sample;
 
 // static
 HistogramBase* SparseHistogram::FactoryGet(const string& name, int32 flags) {
   // TODO(kaiwang): Register and get SparseHistogram with StatisticsRecorder.
   HistogramBase* histogram = new SparseHistogram(name);
   histogram->SetFlags(flags);
   return histogram;
 }
 
 SparseHistogram::~SparseHistogram() {}
 
+HistogramType SparseHistogram::GetHistogramType() const {
+  return SPARSE_HISTOGRAM;
+}
+
 bool SparseHistogram::HasConstructionArguments(Sample minimum,
                                                Sample maximum,
                                                size_t bucket_count) const {
   // SparseHistogram never has min/max/bucket_count limit.
   return false;
 }
 
 void SparseHistogram::Add(Sample value) {
   base::AutoLock auto_lock(lock_);
   sample_counts_[value]++;
@@ skipping 28 matching lines @@
 void SparseHistogram::GetParameters(DictionaryValue* params) const {
   // TODO(kaiwang): Implement. (See HistogramBase::WriteJSON.)
 }
 
 void SparseHistogram::GetCountAndBucketData(Count* count,
                                             ListValue* buckets) const {
   // TODO(kaiwang): Implement. (See HistogramBase::WriteJSON.)
 }
 
 }  // namespace base