Adding reporting of metrics sampling rate.

chrome/browser/metrics/sampling_metrics_provider.h

Index: chrome/browser/metrics/sampling_metrics_provider.h
diff --git a/chrome/browser/metrics/sampling_metrics_provider.h b/chrome/browser/metrics/sampling_metrics_provider.h
new file mode 100644
index 0000000000000000000000000000000000000000..eccefd676796984852ecf117708c692e8d59a0f9
--- /dev/null
+++ b/chrome/browser/metrics/sampling_metrics_provider.h
@@ -0,0 +1,24 @@
+// Copyright 2016 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 CHROME_BROWSER_METRICS_SAMPLING_METRICS_PROVIDER_H_
+#define CHROME_BROWSER_METRICS_SAMPLING_METRICS_PROVIDER_H_
+
+#include "components/metrics/metrics_provider.h"
+
+namespace metrics {

[Alexei Svitkine (slow), 2016/08/01 15:49:56]

Nit: Add an empty line.

[jwd, 2016/08/01 16:45:29]

Done.

+class SamplingMetricsProvider : public MetricsProvider {
+ public:
+  SamplingMetricsProvider();
+  ~SamplingMetricsProvider() override;
+
+  // MetricsProvider:

[Alexei Svitkine (slow), 2016/08/01 15:49:56]

Add private: before this.

[jwd, 2016/08/01 16:45:29]

Done.

+  void ProvideGeneralMetrics(ChromeUserMetricsExtension* uma_proto) override;
+
+  DISALLOW_COPY_AND_ASSIGN(SamplingMetricsProvider);
+};
+
+}  // namespace metrics
+
+#endif  // CHROME_BROWSER_METRICS_SAMPLING_METRICS_PROVIDER_H_