Remove static locals from histograms.

webrtc/base/histogram.h

+/*
+ *  Copyright (c) 2017 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.
+ */
+
+#ifndef WEBRTC_BASE_HISTOGRAM_H_
+#define WEBRTC_BASE_HISTOGRAM_H_
+
+namespace webrtc {
+namespace metrics {
+class Histogram;
+}  // namespace metrics
+}  // namespace webrtc
+
+namespace rtc {
+
+class HistogramBase {
+ protected:
+  enum class Type { kCounts, kCountsLinear, kEnumeration };
+
+  HistogramBase(const char* name,
+                Type type,
+                int min,
+                int max,
+                int bucket_count);
+
+  HistogramBase(const char* name, Type type, int boundary);
+
+  void AddSample(int sample) const;
+
+ private:
+  webrtc::metrics::Histogram* histogram_;
+};
+
+class Histogram : private HistogramBase {
+ public:
+  Histogram(const char* name, int max);
+  Histogram(const char* name, int min, int max);
+  Histogram(const char* name, int min, int max, int bucket_count);
+
+  using HistogramBase::AddSample;
+};
+
+class HistogramLinear : private HistogramBase {
+ public:
+  HistogramLinear(const char* name, int max);
+  HistogramLinear(const char* name, int min, int max);
+  HistogramLinear(const char* name, int min, int max, int bucket_count);
+
+  using HistogramBase::AddSample;
+};
+
+class HistogramEnumeration : private HistogramBase {
+ public:
+  HistogramEnumeration(const char* name, int boundary);
+  void AddSample(int sample);
+
+ private:
+  int boundary_;
+};
+
+class HistogramBoolean : private HistogramEnumeration {
+ public:
+  explicit HistogramBoolean(const char* name);
+
+  void AddSample(bool sample);
+};
+
+class HistogramPercentage : private HistogramEnumeration {
+ public:
+  explicit HistogramPercentage(const char* name);
+
+  using HistogramEnumeration::AddSample;
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_HISTOGRAM_H_