Create a histogram serialization mechanism in components/metrics

components/metrics/export/linearhistogram_sample.cc

+// 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.
+
+#include "components/metrics/export/linearhistogram_sample.h"
+
+#include <string>
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#include "base/strings/stringprintf.h"
+#include "components/metrics/export/metric_sample.h"
+
+namespace metrics {
+
+LinearHistogramSample::LinearHistogramSample(const std::string& histname,
+                                             int sample,
+                                             int max)
+    : MetricSample(MetricSample::LINEAR_HISTOGRAM, histname),
+      sample_(sample),
+      max_(max) {}
+
+LinearHistogramSample::~LinearHistogramSample() {}
+
+std::string LinearHistogramSample::ToString() const {
+  return base::StringPrintf(
+      "linearhistogram%c%s %d %d%c", '\0', name().c_str(), sample_, max_, '\0');
+}
+
+// static
+// Read a linear histogram from a string listing |name|, |sample|, |max|
+// separated by space.

[Alexei Svitkine (slow), 2014/05/01 15:57:09]

Nit: This comment should only say: // static

The real comment about it should be in the .h file.

[bsimonnet, 2014/05/01 20:34:21]

Done.

+scoped_ptr<LinearHistogramSample> LinearHistogramSample::ReadLinearHistogram(
+    const std::string& histogram_serialized) {
+  std::vector<std::string> parts;
+  int sample, max;
+  base::SplitString(histogram_serialized, ' ', &parts);
+  if (parts.size() != 3)
+    return scoped_ptr<LinearHistogramSample>();
+  if (parts[0].length() == 0 || !base::StringToInt(parts[1], &sample) ||
+      !base::StringToInt(parts[2], &max))
+    return scoped_ptr<LinearHistogramSample>();
+
+  return scoped_ptr<LinearHistogramSample>(
+      new LinearHistogramSample(parts[0], sample, max));
+}
+
+}  // namespace metrics