Create a histogram serialization mechanism in components/metrics

base/metrics/linearhistogram_sample_chromeos.h

Index: base/metrics/linearhistogram_sample_chromeos.h
diff --git a/base/metrics/linearhistogram_sample_chromeos.h b/base/metrics/linearhistogram_sample_chromeos.h
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+// Copyright (c) 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 BASE_METRICS_LINEARHISTOGRAM_SAMPLE_CHROMEOS_H
+#define BASE_METRICS_LINEARHISTOGRAM_SAMPLE_CHROMEOS_H
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/metrics/metric_sample_chromeos.h"
+
+namespace base {
+// Represents a linear histogram sample (called Enum too).
+// This class is meant to be used to serialize and deserialize samples to send
+// them from chrome os to chrome.
+class BASE_EXPORT LinearHistogramSample : public MetricSample {
+ public:
+  LinearHistogramSample(const std::string& histname, int sample, int max);
+  virtual ~LinearHistogramSample();
+
+  int sample() const;
+  int max() const;
+  // Returns the serialized version of the sample in the format:
+  // linearhistogram\0|name_| |sample_| |max_|\0
+  virtual string ToString() const OVERRIDE;
+
+  // static
+  // 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:
+  int sample_, max_;
+};
+}  // namespace base
+#endif  // BASE_METRICS_LINEARHISTOGRAM_SAMPLE_CHROMEOS_H