Create a histogram serialization mechanism in components/metrics

base/metrics/useraction_sample_chromeos.h

+// 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_CHROMEOS_USERACTION_SAMPLE_CHROMEOS_H
+#define BASE_METRICS_CHROMEOS_USERACTION_SAMPLE_CHROMEOS_H
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/metrics/metric_sample_chromeos.h"
+
+using std::string;

[Alexei Svitkine (slow), 2014/04/17 16:33:21]

Nit: Remove and fully-qualify string. Please fix throughout for all std library
using decls.

+
+namespace base {

[Alexei Svitkine (slow), 2014/04/17 16:33:21]

Nit: Please add a blank line after this. Fix throughout.

+// 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 string ToString() const OVERRIDE;
+
+  // static

[Alexei Svitkine (slow), 2014/04/17 16:33:21]

No need for "// static" comment in header file. Put it above the function
implementation in the .cc file instead.

+  // 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);
+};
+}  // namespace base

[Alexei Svitkine (slow), 2014/04/17 16:33:21]

Please add a blank line before this. Please fix throughout.

+#endif  // BASE_METRICS_CHROMEOS_USERACTION_SAMPLE_CHROMEOS_H

[Alexei Svitkine (slow), 2014/04/17 16:33:21]

Please add a blank line before this. Please fix throughout.