content/browser/power_usage_monitor_impl.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_
   6 #define CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/containers/hash_tables.h"
  10 #include "base/gtest_prod_util.h"
  11 #include "base/memory/singleton.h"
  12 #include "base/power_monitor/power_monitor.h"
  13 #include "base/time/time.h"
  14 #include "content/common/content_export.h"
  15 #include "content/public/browser/browser_message_filter.h"
  16 #include "content/public/browser/notification_observer.h"
  17 #include "content/public/browser/notification_registrar.h"
  18 #include "device/battery/battery_status_service.h"
  19
  20 namespace content {
  21
  22 // Record statistics on power usage.
  23 //
  24 // Two main statics are recorded by this class:
  25 // * Power.BatteryDischarge_{5,15,30} - delta between battery level when
  26 //   unplugged from wallpower, over the specified period - in minutes.
  27 // * Power.BatteryDischargeRateWhenUnplugged - the rate of battery discharge
  28 //   from the device being unplugged until it's plugged back in, if said period
  29 //   was longer than 30 minutes.
  30 //
  31 // Heuristics:
  32 // * Data collection starts after system uptime exceeds 30 minutes.
  33 // * If the machine goes to sleep or all renderers are closed then the current
  34 //   measurement is cancelled.
  35 class CONTENT_EXPORT PowerUsageMonitor : public base::PowerObserver,
  36                                          public NotificationObserver {
  37  public:
  38   class SystemInterface {
  39    public:
  40     virtual ~SystemInterface() {}
  41
  42     virtual void ScheduleHistogramReport(base::TimeDelta delay) = 0;
  43     virtual void CancelPendingHistogramReports() = 0;
  44
  45     // Record the battery discharge percent per hour over the time the system
  46     // is on battery power, legal values [0,100].
  47     virtual void RecordDischargePercentPerHour(int percent_per_hour) = 0;
  48
  49     // Allow tests to override clock.
  50     virtual base::Time Now() = 0;
  51   };
  52
  53  public:
  54   PowerUsageMonitor();
  55   ~PowerUsageMonitor() override;
  56
  57   double discharge_amount() const {
  58     return initial_battery_level_ - current_battery_level_;
  59   }
  60
  61   // Start monitoring power usage.
  62   // Note that the actual monitoring will be delayed until 30 minutes after
  63   // system boot.
  64   void Start();
  65
  66   void SetSystemInterfaceForTest(scoped_ptr<SystemInterface> interface);
  67
  68   // Overridden from base::PowerObserver:
  69   void OnPowerStateChange(bool on_battery_power) override;
  70   void OnResume() override;
  71   void OnSuspend() override;
  72
  73   // Overridden from NotificationObserver:
  74   void Observe(int type,
  75                const NotificationSource& source,
  76                const NotificationDetails& details) override;
  77
  78  private:
  79   friend class PowerUsageMonitorTest;
  80   FRIEND_TEST_ALL_PREFIXES(PowerUsageMonitorTest, OnBatteryStatusUpdate);
  81   FRIEND_TEST_ALL_PREFIXES(PowerUsageMonitorTest, OnRenderProcessNotification);
  82
  83   // Start monitoring system power usage.
  84   // This function may be called after a delay, see Start() for details.
  85   void StartInternal();
  86
  87   void OnBatteryStatusUpdate(const device::BatteryStatus& status);
  88   void OnRenderProcessNotification(int type, int rph_id);
  89
  90   void DischargeStarted(double battery_level);
  91   void WallPowerConnected(double battery_level);
  92
  93   void CancelPendingHistogramReporting();
  94
  95   device::BatteryStatusService::BatteryUpdateCallback callback_;
  96   scoped_ptr<device::BatteryStatusService::BatteryUpdateSubscription>
  97       subscription_;
  98
  99   NotificationRegistrar registrar_;
 100
 101   scoped_ptr<SystemInterface> system_interface_;
 102
 103   // True if monitoring was started (Start() called).
 104   bool started_;
 105
 106   // True if collecting metrics for the current discharge cycle e.g. if no
 107   // renderers are open we don't keep track of discharge.
 108   bool tracking_discharge_;
 109
 110   // True if the system is running on battery power, false if on wall power.
 111   bool on_battery_power_;
 112
 113   // Battery level when wall power disconnected. [0.0, 1.0] - 0 if on wall
 114   // power, 1 means fully charged.
 115   double initial_battery_level_;
 116
 117   // Current battery level. [0.0, 1.0] - 0 if on wall power, 1 means fully
 118   // charged.
 119   double current_battery_level_;
 120
 121   // Timestamp when wall power was disconnected, null Time object otherwise.
 122   base::Time start_discharge_time_;
 123
 124   // IDs of live renderer processes.
 125   base::hash_set<int> live_renderer_ids_;
 126
 127  private:
 128   DISALLOW_COPY_AND_ASSIGN(PowerUsageMonitor);
 129 };
 130
 131 }  // namespace content
 132
 133 #endif  // CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_