Create a histogram serialization mechanism in components/metrics

components/metrics/useraction_sample_chromeos.h

Index: components/metrics/useraction_sample_chromeos.h
diff --git a/components/metrics/useraction_sample_chromeos.h b/components/metrics/useraction_sample_chromeos.h
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+++ b/components/metrics/useraction_sample_chromeos.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_CHROMEOS_USERACTION_SAMPLE_CHROMEOS_H
+#define COMPONENTS_METRICS_CHROMEOS_USERACTION_SAMPLE_CHROMEOS_H
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "components/metrics/metric_sample_chromeos.h"
+
+namespace metrics {
+
+// Represents a logged action.
+// This class is meant to be used to serialize and deserialize samples to
+// send them from chromeOS to chrome.
+class BASE_EXPORT UserActionSample : public MetricSample {
+ public:
+  explicit UserActionSample(const std::string& action);
+  virtual ~UserActionSample();
+
+  // Returns a serialized version of the sample on the format:
+  // useraction\0|name_|\0
+  virtual std::string ToString() const OVERRIDE;
+
+  // Deserialize a sample passed as a string.
+  // Returns a UserActionSample if the deserialization is successful and NULL
+  // otherwise.
+  static UserActionSample* ReadUserAction(const std::string& useraction);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(UserActionSample);
+};
+
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_CHROMEOS_USERACTION_SAMPLE_CHROMEOS_H