Adds UMA metrics for renderer uptime

chrome/browser/metrics/renderer_uptime_metrics_provider.h

+// Copyright 2017 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_RENDERER_UPTIME_METRICS_PROVIDER_H_
+#define CHROME_BROWSER_METRICS_RENDERER_UPTIME_METRICS_PROVIDER_H_
+
+#include "components/metrics/metrics_provider.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+// ChromeStabilityMetricsProvider gathers and logs Chrome-specific stability-
+// related metrics.
+class RendererUptimeMetricsProvider : public metrics::MetricsProvider,
+                                      public content::NotificationObserver {
+ public:
+  RendererUptimeMetricsProvider();
+
+  // metrics::MetricsProvider:
+  void OnRecordingEnabled() override;
+  void OnRecordingDisabled() override;
+
+  // content::NotificationObserver:
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
+
+ private:
+  // Registrar for receiving stability-related notifications.
+  content::NotificationRegistrar registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(RendererUptimeMetricsProvider);
+};
+
+#endif  // CHROME_BROWSER_METRICS_RENDERER_UPTIME_METRICS_PROVIDER_H_