Create a histogram serialization mechanism in components/metrics

components/metrics/export/useraction_sample.h

Index: components/metrics/export/useraction_sample.h
diff --git a/components/metrics/export/useraction_sample.h b/components/metrics/export/useraction_sample.h
new file mode 100644
index 0000000000000000000000000000000000000000..c58ba2db53390477535c3f0eea71901882f82017
--- /dev/null
+++ b/components/metrics/export/useraction_sample.h
@@ -0,0 +1,39 @@
+// 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_USERACTION_SAMPLE_H_
+#define COMPONENTS_METRICS_EXPORT_USERACTION_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 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();
+
+  // Return 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_EXPORT_USERACTION_SAMPLE_H_