metrics/base: log whether drives have seek penalties.

chrome/browser/metrics/disk_metrics_provider.h

+// Copyright 2015 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_DISK_METRICS_PROVIDER_H_

[Alexei Svitkine (slow), 2015/03/12 16:41:06]

Can this class live in the component? Since it just depends on base.

[Dan Beam, 2015/03/13 19:31:32]

look at the cc dependencies

+#define CHROME_BROWSER_METRICS_DISK_METRICS_PROVIDER_H_
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "components/metrics/metrics_provider.h"
+
+struct SeekPenaltyResponse {
+  SeekPenaltyResponse();
+  bool success;
+  bool has_seek_penalty;
+};
+
+struct DiskMetrics {

[Alexei Svitkine (slow), 2015/03/12 16:41:06]

Can these be declared inside the class? That way, we're not polluting the global
namespace.

[Dan Beam, 2015/03/13 19:31:32]

yes, Done.

+  SeekPenaltyResponse app_disk;
+  SeekPenaltyResponse user_data_disk;
+};
+
+// Provides metrics about the local disks on a user's computer. Currently only
+// checks to see if they incur a seek-time penalty (e.g. if they're SSDs).
+class DiskMetricsProvider : public metrics::MetricsProvider {
+ public:
+  DiskMetricsProvider();
+  ~DiskMetricsProvider() override;
+
+  // metrics::MetricsDataProvider:
+  void ProvideSystemProfileMetrics(
+      metrics::SystemProfileProto* system_profile_proto) override;
+
+ private:
+  void GotDiskMetrics(const DiskMetrics& metrics);

[Alexei Svitkine (slow), 2015/03/12 16:41:06]

Add a comment.

[Dan Beam, 2015/03/13 19:31:32]

Done.

+
+  DiskMetrics metrics_;
+
+  base::ThreadChecker thread_checker_;
+  base::WeakPtrFactory<DiskMetricsProvider> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DiskMetricsProvider);
+};
+
+#endif  // CHROME_BROWSER_METRICS_DISK_METRICS_PROVIDER_H_