Componentize DriveMetricsProvider*

chrome/browser/metrics/drive_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_DRIVE_METRICS_PROVIDER_H_
-#define CHROME_BROWSER_METRICS_DRIVE_METRICS_PROVIDER_H_
-
-#include "base/callback.h"
-#include "base/gtest_prod_util.h"
-#include "base/macros.h"
-#include "base/memory/weak_ptr.h"
-#include "base/threading/thread_checker.h"
-#include "components/metrics/metrics_provider.h"
-#include "components/metrics/proto/system_profile.pb.h"
-
-namespace base {
-class FilePath;
-}
-
-// Provides metrics about the local drives on a user's computer. Currently only
-// checks to see if they incur a seek-time penalty (e.g. if they're SSDs).
-//
-// Defers gathering metrics until after "rush hour" (startup) so as to not bog
-// down the FILE thread.
-class DriveMetricsProvider : public metrics::MetricsProvider {
- public:
-  DriveMetricsProvider();
-  ~DriveMetricsProvider() override;
-
-  // metrics::MetricsDataProvider:
-  void ProvideSystemProfileMetrics(
-      metrics::SystemProfileProto* system_profile_proto) override;
-
-  // Called by ChromeMetricsServiceClient to start gathering metrics.
-  void GetDriveMetrics(const base::Closure& done);
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(DriveMetricsProviderTest, HasSeekPenalty);
-
-  // A response to querying a drive as to whether it incurs a seek penalty.
-  // |has_seek_penalty| is set if |success| is true.
-  struct SeekPenaltyResponse {
-    SeekPenaltyResponse();
-    bool success;
-    bool has_seek_penalty;
-  };
-
-  struct DriveMetrics {
-    SeekPenaltyResponse app_drive;
-    SeekPenaltyResponse user_data_drive;
-  };
-
-  // Determine whether the device that services |path| has a seek penalty.
-  // Returns false if it couldn't be determined (e.g., |path| doesn't exist).
-  static bool HasSeekPenalty(const base::FilePath& path,
-                             bool* has_seek_penalty);
-
-  // Gather metrics about various drives on the FILE thread.
-  static DriveMetrics GetDriveMetricsOnFileThread();
-
-  // Tries to determine whether there is a penalty for seeking on the drive that
-  // hosts |path_service_key| (for example: the drive that holds "Local State").
-  static void QuerySeekPenalty(int path_service_key,
-                               SeekPenaltyResponse* response);
-
-  // Called when metrics are done being gathered from the FILE thread.
-  void GotDriveMetrics(const DriveMetrics& metrics);
-
-  // Fills |drive| with information from successful |response|s.
-  void FillDriveMetrics(
-      const SeekPenaltyResponse& response,
-      metrics::SystemProfileProto::Hardware::Drive* drive);
-
-  // Information gathered about various important drives.
-  DriveMetrics metrics_;
-
-  // Called when metrics are done being collected.
-  base::Closure got_metrics_callback_;
-
-  base::ThreadChecker thread_checker_;
-  base::WeakPtrFactory<DriveMetricsProvider> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(DriveMetricsProvider);
-};
-
-#endif  // CHROME_BROWSER_METRICS_DRIVE_METRICS_PROVIDER_H_