Decouple PowerUsageMonitor{Impl} from //content/browser

content/browser/power_usage_monitor_impl.h

-// 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.
-
-#ifndef CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_
-#define CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_
-
-#include "base/containers/hash_tables.h"
-#include "base/gtest_prod_util.h"
-#include "base/macros.h"
-#include "base/memory/singleton.h"
-#include "base/power_monitor/power_monitor.h"
-#include "base/time/time.h"
-#include "content/common/content_export.h"
-#include "content/public/browser/browser_message_filter.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-#include "device/battery/battery_status_service.h"
-
-namespace content {
-
-// Record statistics on power usage.
-//
-// Two main statics are recorded by this class:
-// * Power.BatteryDischarge_{5,15,30} - delta between battery level when
-//   unplugged from wallpower, over the specified period - in minutes.
-// * Power.BatteryDischargeRateWhenUnplugged - the rate of battery discharge
-//   from the device being unplugged until it's plugged back in, if said period
-//   was longer than 30 minutes.
-//
-// Heuristics:
-// * Data collection starts after system uptime exceeds 30 minutes.
-// * If the machine goes to sleep or all renderers are closed then the current
-//   measurement is cancelled.
-class CONTENT_EXPORT PowerUsageMonitor : public base::PowerObserver,
-                                         public NotificationObserver {
- public:
-  class SystemInterface {
-   public:
-    virtual ~SystemInterface() {}
-
-    virtual void ScheduleHistogramReport(base::TimeDelta delay) = 0;
-    virtual void CancelPendingHistogramReports() = 0;
-
-    // Record the battery discharge percent per hour over the time the system
-    // is on battery power, legal values [0,100].
-    virtual void RecordDischargePercentPerHour(int percent_per_hour) = 0;
-
-    // Allow tests to override clock.
-    virtual base::Time Now() = 0;
-  };
-
- public:
-  PowerUsageMonitor();
-  ~PowerUsageMonitor() override;
-
-  double discharge_amount() const {
-    return initial_battery_level_ - current_battery_level_;
-  }
-
-  // Start monitoring power usage.
-  // Note that the actual monitoring will be delayed until 30 minutes after
-  // system boot.
-  void Start();
-
-  void SetSystemInterfaceForTest(std::unique_ptr<SystemInterface> interface);
-
-  // Overridden from base::PowerObserver:
-  void OnPowerStateChange(bool on_battery_power) override;
-  void OnResume() override;
-  void OnSuspend() override;
-
-  // Overridden from NotificationObserver:
-  void Observe(int type,
-               const NotificationSource& source,
-               const NotificationDetails& details) override;
-
- private:
-  friend class PowerUsageMonitorTest;
-  FRIEND_TEST_ALL_PREFIXES(PowerUsageMonitorTest, OnBatteryStatusUpdate);
-  FRIEND_TEST_ALL_PREFIXES(PowerUsageMonitorTest, OnRenderProcessNotification);
-
-  // Start monitoring system power usage.
-  // This function may be called after a delay, see Start() for details.
-  void StartInternal();
-
-  void OnBatteryStatusUpdate(const device::BatteryStatus& status);
-  void OnRenderProcessNotification(int type, int rph_id);
-
-  void DischargeStarted(double battery_level);
-  void WallPowerConnected(double battery_level);
-
-  void CancelPendingHistogramReporting();
-
-  device::BatteryStatusService::BatteryUpdateCallback callback_;
-  std::unique_ptr<device::BatteryStatusService::BatteryUpdateSubscription>
-      subscription_;
-
-  NotificationRegistrar registrar_;
-
-  std::unique_ptr<SystemInterface> system_interface_;
-
-  // True if monitoring was started (Start() called).
-  bool started_;
-
-  // True if collecting metrics for the current discharge cycle e.g. if no
-  // renderers are open we don't keep track of discharge.
-  bool tracking_discharge_;
-
-  // True if the system is running on battery power, false if on wall power.
-  bool on_battery_power_;
-
-  // Battery level when wall power disconnected. [0.0, 1.0] - 0 if on wall
-  // power, 1 means fully charged.
-  double initial_battery_level_;
-
-  // Current battery level. [0.0, 1.0] - 0 if on wall power, 1 means fully
-  // charged.
-  double current_battery_level_;
-
-  // Timestamp when wall power was disconnected, null Time object otherwise.
-  base::Time start_discharge_time_;
-
-  // IDs of live renderer processes.
-  base::hash_set<int> live_renderer_ids_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(PowerUsageMonitor);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_