Create a histogram serialization mechanism in components/metrics

components/metrics/export/histogram_sample.h

+// Copyright 2014 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.
+
+#ifndef COMPONENTS_METRICS_EXPORT_HISTOGRAM_SAMPLE_H_
+#define COMPONENTS_METRICS_EXPORT_HISTOGRAM_SAMPLE_H_
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "components/metrics/export/metric_sample.h"
+
+namespace metrics {
+
+// Represent a single histogram sample.
+// This class is meant to be used to serialize and deserialize samples to send
+// them from ChromeOS to Chrome.
+class BASE_EXPORT HistogramSample : public MetricSample {
+ public:
+  HistogramSample(const std::string& name,
+                  int sample,
+                  int min,
+                  int max,
+                  int nbucket);
+  virtual ~HistogramSample();
+
+  int sample() const { return sample_; }
+  int min() const { return min_; }
+  int max() const { return max_; }
+  int nbucket() const { return nbucket_; }
+
+  // Return the sample serialized on the format:
+  // histogram\0|name_| |sample_| |min_| |max_| |nbucket_|\0
+  virtual std::string ToString() const OVERRIDE;
+
+  // Deserialize a histogram passed as a string.
+  // Returns a HistogramSample if the deserialization is successful, otherwise
+  // returns NULL.
+  static scoped_ptr<HistogramSample> ReadHistogram(
+      const std::string& serialized_histogram);
+
+ private:
+  const int sample_;
+  const int min_;
+  const int max_;
+  const int nbucket_;
+
+  DISALLOW_COPY_AND_ASSIGN(HistogramSample);
+};
+
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_EXPORT_HISTOGRAM_SAMPLE_H_