Create a histogram serialization mechanism in components/metrics

components/metrics/export/metric_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/metric_sample.h"
+
+#include <string>
+
+namespace metrics {
+
+MetricSample::MetricSample(MetricSample::SampleType sample_type,
+                           const std::string& metric_name)
+    : type_(sample_type), name_(metric_name) {}
+
+MetricSample::~MetricSample() {}
+
+bool MetricSample::IsValid() const {
+  return name().find(' ') == std::string::npos &&
+         name().find('\0') == std::string::npos && name().length() > 0;
+}
+
+std::string MetricSample::ToString() const {
+  return "not implemented";
+}
+
+}  // namespace metrics