Create a histogram serialization mechanism in components/metrics

components/metrics/export/histogram_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/histogram_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 {
+
+HistogramSample::HistogramSample(const std::string& name,
+                                 int sample,
+                                 int min,
+                                 int max,
+                                 int nbucket)
+    : MetricSample(MetricSample::HISTOGRAM, name),
+      sample_(sample),
+      min_(min),
+      max_(max),
+      nbucket_(nbucket) {}
+
+HistogramSample::~HistogramSample() {}
+
+std::string HistogramSample::ToString() const {
+  return base::StringPrintf("histogram%c%s %d %d %d %d%c",
+                            '\0',
+                            name().c_str(),
+                            sample_,
+                            min_,
+                            max_,
+                            nbucket_,
+                            '\0');
+}
+
+// static
+// Read a histogram from a string listing |name|, |sample|, |min|, |max|,
+// |nbucket| separated by a space.
+scoped_ptr<HistogramSample> HistogramSample::ReadHistogram(
+    const std::string& histogram_serialized) {
+  std::vector<std::string> parts;
+  base::SplitString(histogram_serialized, ' ', &parts);
+  if (parts.size() != 5)
+    return scoped_ptr<HistogramSample>();
+  int sample, min, max, nbucket;
+  if (parts[0].length() == 0 || !base::StringToInt(parts[1], &sample) ||
+      !base::StringToInt(parts[2], &min) ||
+      !base::StringToInt(parts[3], &max) ||
+      !base::StringToInt(parts[4], &nbucket))

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

Nit: {}

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

Done.

+    return scoped_ptr<HistogramSample>();
+
+  return scoped_ptr<HistogramSample>(
+      new HistogramSample(parts[0], sample, min, max, nbucket));
+}
+
+}  // namespace metrics