Create a histogram serialization mechanism in components/metrics

components/metrics/export/linearhistogram_sample.h

Index: components/metrics/export/linearhistogram_sample.h
diff --git a/components/metrics/export/linearhistogram_sample.h b/components/metrics/export/linearhistogram_sample.h
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+++ b/components/metrics/export/linearhistogram_sample.h
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+// 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_LINEARHISTOGRAM_SAMPLE_H_
+#define COMPONENTS_METRICS_EXPORT_LINEARHISTOGRAM_SAMPLE_H_
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "components/metrics/export/metric_sample.h"
+
+namespace metrics {
+
+// Represent a linear histogram sample (called Enum too).
+// This class is meant to be used to serialize and deserialize samples to send
+// them from ChromeOS to Chrome.
+class BASE_EXPORT LinearHistogramSample : public MetricSample {
+ public:
+  LinearHistogramSample(const std::string& name, int sample, int max);
+  virtual ~LinearHistogramSample();
+
+  int sample() const { return sample_; }
+  int max() const { return max_; }
+
+  // Return the serialized version of the sample in the format:
+  // linearhistogram\0|name_| |sample_| |max_|\0
+  virtual std::string ToString() const OVERRIDE;
+
+  // Deserialize a sample passed as a string.
+  // Returns a LinearHistogram if the deserialization is successful.
+  // Returns NULL if the deserialization fails.
+  static LinearHistogramSample* ReadLinearHistogram(
+      const std::string& serialized_histogram);
+
+ private:
+  const int sample_, max_;
+
+  DISALLOW_COPY_AND_ASSIGN(LinearHistogramSample);
+};
+
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_EXPORT_LINEARHISTOGRAM_SAMPLE_H_