Create a histogram serialization mechanism in components/metrics

base/metrics/linearhistogram_sample.cc

Index: base/metrics/linearhistogram_sample.cc
diff --git a/base/metrics/linearhistogram_sample.cc b/base/metrics/linearhistogram_sample.cc
new file mode 100644
index 0000000000000000000000000000000000000000..24e8951e00d1ea8a45ecf3082ecce7eec4109f51
--- /dev/null
+++ b/base/metrics/linearhistogram_sample.cc
@@ -0,0 +1,50 @@
+// 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.
+
+#include <string>
+
+#include "base/logging.h"
+#include "base/metrics/chromeos_metrics.h"
+#include "base/metrics/linearhistogram_sample.h"
+#include "base/metrics/metric_sample.h"
+
+using std::string;
+
+namespace base {
+LinearHistogramSample::LinearHistogramSample(const std::string& histname,
+  int sample, int max):
+  MetricSample(MetricSample::LINEAR_HISTOGRAM) {
+  name_ = histname;
+  sample_ = sample;
+  max_ = max;
+}
+
+std::string LinearHistogramSample::name() {
+  return name_;
+}
+
+int LinearHistogramSample::sample() {
+  return sample_;
+}
+
+int LinearHistogramSample::max() {
+  return max_;
+}
+
+LinearHistogramSample* LinearHistogramSample::ReadLinearHistogram(
+    const std::string& hist_repr) {
+  int sample, max;
+  char name[128];
+  sscanf(hist_repr.c_str(), "%127s %d %d", name, &sample, &max);

[achaulk, 2014/04/07 22:16:00]

Need to check return. Might want to note that spaces are illegal in names

+  return new LinearHistogramSample(name, sample, max);
+}
+
+LinearHistogramSample::~LinearHistogramSample() {}
+
+int LinearHistogramSample::Write(int buffer_size, char* buffer) {
+  return ChromeOSMetrics::FormatSample(buffer_size, buffer,
+                              "linearhistogram%c%s %d %d", '\0', name_.c_str(),

[achaulk, 2014/04/07 22:16:00]

Why not inline \0? Also indentation

[bsimonnet, 2014/04/08 23:00:09]

the compiler complains when I embed the \0 in a format string. Is there a way to
go around ?

+                              sample_, max_);
+}
+}  // namespace base