Report UMA stats on battery discharge rate when Chrome is running.
Stats reported:
* Battery depletion percent over 5, 15 and 30 minute period.
* Battery discharge rate if battery was discharged for more than 30 minutes.
Reports are only generated after 30 minutes of uptime so as not to be affected by increased power draw at system startup.
In-progress stat collection is cancelled on sleep or when all renderers are closed.
BUG=418407
Review URL: https://codereview.chromium.org/560553005
Cr-Commit-Position: refs/heads/master@{#304412}
diff --git a/content/browser/power_usage_monitor_impl.h b/content/browser/power_usage_monitor_impl.h
new file mode 100644
index 0000000..06216bb
--- /dev/null
+++ b/content/browser/power_usage_monitor_impl.h
@@ -0,0 +1,133 @@
+// 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 CHROME_CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_
+#define CHROME_CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_
+
+#include "base/basictypes.h"
+#include "base/containers/hash_tables.h"
+#include "base/gtest_prod_util.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(scoped_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_;
+ scoped_ptr<device::BatteryStatusService::BatteryUpdateSubscription>
+ subscription_;
+
+ NotificationRegistrar registrar_;
+
+ scoped_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 // CHROME_CONTENT_BROWSER_POWER_USAGE_MONITOR_IMPL_H_
