Add linearly spaced counting histograms

webrtc/system_wrappers/source/metrics_default.cc

 // Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the LICENSE file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS.  All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 //
 
 #include "webrtc/system_wrappers/include/metrics_default.h"
@@ skipping 195 matching lines @@
 // webrtc/system_wrappers/interface/metrics.h.
 
 // Histogram with exponentially spaced buckets.
 // Creates (or finds) histogram.
 // The returned histogram pointer is cached (and used for adding samples in
 // subsequent calls).
 Histogram* HistogramFactoryGetCounts(const std::string& name,
                                      int min,
                                      int max,
                                      int bucket_count) {
+  // TODO(asapersson): Alternative implementation will be needed if this
+  // histogram type should be truly exponential.
+  return HistogramFactoryGetCountsLinear(name, min, max, bucket_count);
+}
+
+// Histogram with linearly spaced buckets.
+// Creates (or finds) histogram.
+// The returned histogram pointer is cached (and used for adding samples in
+// subsequent calls).
+Histogram* HistogramFactoryGetCountsLinear(const std::string& name,
+                                           int min,
+                                           int max,
+                                           int bucket_count) {
   RtcHistogramMap* map = GetMap();
   if (!map)
     return nullptr;
 
   return map->GetCountsHistogram(name, min, max, bucket_count);
 }
 
 // Histogram with linearly spaced buckets.
 // Creates (or finds) histogram.
 // The returned histogram pointer is cached (and used for adding samples in
@@ skipping 59 matching lines @@
   return map ? map->NumSamples(name) : 0;
 }
 
 int MinSample(const std::string& name) {
   RtcHistogramMap* map = GetMap();
   return map ? map->MinSample(name) : -1;
 }
 
 }  // namespace metrics
 }  // namespace webrtc