android: Move battery metrics impl from chrome/ to components/

This moves the majority of AndroidBatteryMetrics from chrome/ to
components/, so that we can reuse it for WebView/WebLayer in the future.

The only aspect that remains in chrome/ is the detection of the app's
visibility state, since this will have to be done some other way for
WebView.

Bug: 1102048
Change-Id: Ia8391fd5efd80411ac970c559cdf5db988ba9ea4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2485794
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819432}

chrome/browser/BUILD.gn

@@ -2413,8 +2413,6 @@ static_library("browser") {
       "android/background_task_scheduler/chrome_background_task_factory.h",
       "android/background_task_scheduler/proxy_native_task.cc",
       "android/background_task_scheduler/proxy_native_task.h",
-      "android/battery/android_battery_metrics.cc",
-      "android/battery/android_battery_metrics.h",
       "android/bookmarks/bookmark_bridge.cc",
       "android/bookmarks/bookmark_bridge.h",
       "android/bookmarks/partner_bookmarks_reader.cc",
@@ -3186,6 +3184,7 @@ static_library("browser") {
       "//components/payments/content/android",
       "//components/payments/content/android:jni_headers",
       "//components/permissions/android:native",
+      "//components/power_metrics",
       "//components/query_tiles",
       "//components/resources:android_resources",
       "//components/resources:components_resources",

chrome/browser/DEPS

@@ -216,6 +216,7 @@ include_rules = [
   "+components/permissions",
   "+components/pdf/browser",
   "+components/policy",
+  "+components/power_metrics",
   "+components/pref_registry",
   "+components/prefs",
   "+components/prerender",

chrome/browser/battery/battery_metrics.cc

@@ -22,10 +22,30 @@ BatteryMetrics::BatteryMonitorBinder& GetBinderOverride() {
   return *binder;
 }
 
+#if defined(OS_ANDROID)
+bool IsAppVisible(base::android::ApplicationState state) {
+  return state == base::android::APPLICATION_STATE_HAS_RUNNING_ACTIVITIES;
+}
+#endif  // defined(OS_ANDROID)
+
 }  // namespace
 
 BatteryMetrics::BatteryMetrics() {
   StartRecording();
+
+#if defined(OS_ANDROID)
+  // On Android, also track the battery capacity drain while Chrome is the
+  // foreground activity.
+  app_state_listener_ =
+      base::android::ApplicationStatusListener::New(base::BindRepeating(
+          [](BatteryMetrics* metrics, base::android::ApplicationState state) {
+            metrics->android_metrics_.OnAppVisibilityChanged(
+                IsAppVisible(state));
+          },
+          base::Unretained(this)));
+  android_metrics_.OnAppVisibilityChanged(
+      IsAppVisible(base::android::ApplicationStatusListener::GetState()));
+#endif  // defined(OS_ANDROID)
 }
 
 BatteryMetrics::~BatteryMetrics() = default;

chrome/browser/battery/battery_metrics.h

@@ -17,7 +17,8 @@
 #include "services/device/public/mojom/battery_status.mojom-forward.h"
 
 #if defined(OS_ANDROID)
-#include "chrome/browser/android/battery/android_battery_metrics.h"
+#include "base/android/application_status_listener.h"
+#include "components/power_metrics/android_battery_metrics.h"
 #endif  // defined(OS_ANDROID)
 
 // Records metrics around battery usage on all platforms. Connects to
@@ -55,7 +56,8 @@ class BatteryMetrics {
   mojo::Remote<device::mojom::BatteryMonitor> battery_monitor_;
 
 #if defined(OS_ANDROID)
-  AndroidBatteryMetrics android_metrics_;
+  power_metrics::AndroidBatteryMetrics android_metrics_;
+  std::unique_ptr<base::android::ApplicationStatusListener> app_state_listener_;
 #endif  // defined(OS_ANDROID)
 
   SEQUENCE_CHECKER(sequence_checker_);

components/power_metrics/BUILD.gn

+# Copyright 2020 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.
+
+if (is_android) {
+  static_library("power_metrics") {
+    sources = [
+      "android_battery_metrics.cc",
+      "android_battery_metrics.h",
+    ]
+
+    deps = [
+      "//base",
+      "//net",
+    ]
+  }
+}

components/power_metrics/DEPS

+include_rules = [
+  "+net/android",
+]

components/power_metrics/OWNERS

+eseckler@chromium.org
+skyostil@chromium.org
+khokhlov@google.com
+
+# COMPONENT: Speed>Metrics

chrome/browser/android/battery/android_battery_metrics.cc → components/power_metrics/android_battery_metrics.cc

@@ -2,17 +2,19 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/android/battery/android_battery_metrics.h"
+#include "components/power_metrics/android_battery_metrics.h"
 
 #include "base/android/radio_utils.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/optional.h"
 #include "base/power_monitor/power_monitor.h"
 #include "net/android/network_library.h"
 #include "net/android/traffic_stats.h"
 
+namespace power_metrics {
 namespace {
 
 void Report30SecondRadioUsage(int64_t tx_bytes, int64_t rx_bytes) {
@@ -115,10 +117,7 @@ void ReportAveragedDrain(int capacity_consumed,
 constexpr base::TimeDelta AndroidBatteryMetrics::kMetricsInterval;
 
 AndroidBatteryMetrics::AndroidBatteryMetrics()
-    : app_state_listener_(base::android::ApplicationStatusListener::New(
-          base::BindRepeating(&AndroidBatteryMetrics::OnAppStateChanged,
-                              base::Unretained(this)))),
-      app_state_(base::android::ApplicationStatusListener::GetState()),
+    : app_visible_(false),
       on_battery_power_(base::PowerMonitor::IsOnBatteryPower()) {
   base::PowerMonitor::AddObserver(this);
   UpdateMetricsEnabled();
@@ -128,10 +127,9 @@ AndroidBatteryMetrics::~AndroidBatteryMetrics() {
   base::PowerMonitor::RemoveObserver(this);
 }
 
-void AndroidBatteryMetrics::OnAppStateChanged(
-    base::android::ApplicationState state) {
+void AndroidBatteryMetrics::OnAppVisibilityChanged(bool visible) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  app_state_ = state;
+  app_visible_ = visible;
   UpdateMetricsEnabled();
 }
 
@@ -144,12 +142,10 @@ void AndroidBatteryMetrics::OnPowerStateChange(bool on_battery_power) {
 void AndroidBatteryMetrics::UpdateMetricsEnabled() {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
-  // We want to attribute battery drain to Chrome while it is in the foreground.
-  // Battery drain will only be reflected in remaining battery capacity when the
-  // device is not on a charger.
-  bool should_be_enabled =
-      app_state_ == base::android::APPLICATION_STATE_HAS_RUNNING_ACTIVITIES &&
-      on_battery_power_;
+  // We want to attribute battery drain to chromium while the embedding app is
+  // visible. Battery drain will only be reflected in remaining battery capacity
+  // when the device is not on a charger.
+  bool should_be_enabled = app_visible_ && on_battery_power_;
 
   if (should_be_enabled && !metrics_timer_.IsRunning()) {
     // Capture first capacity measurement and enable the repeating timer.
@@ -237,3 +233,5 @@ void AndroidBatteryMetrics::CaptureAndReportMetrics() {
 bool AndroidBatteryMetrics::IsMeasuringDrainExclusively() const {
   return observed_capacity_drops_ >= 2;
 }
+
+}  // namespace power_metrics

chrome/browser/android/battery/android_battery_metrics.h → components/power_metrics/android_battery_metrics.h

@@ -2,44 +2,47 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_ANDROID_BATTERY_ANDROID_BATTERY_METRICS_H_
-#define CHROME_BROWSER_ANDROID_BATTERY_ANDROID_BATTERY_METRICS_H_
+#ifndef COMPONENTS_POWER_METRICS_ANDROID_BATTERY_METRICS_H_
+#define COMPONENTS_POWER_METRICS_ANDROID_BATTERY_METRICS_H_
 
-#include "base/android/application_status_listener.h"
 #include "base/macros.h"
 #include "base/power_monitor/power_observer.h"
 #include "base/sequence_checker.h"
 #include "base/timer/timer.h"
 
-// Records metrics around battery usage on Android.
+namespace power_metrics {
+
+// Records metrics around battery usage on Android. The metrics are only tracked
+// while the device is not charging and the app is visible (embedder should call
+// OnAppVisibilityChanged()). This class is not thread-safe.
 class AndroidBatteryMetrics : public base::PowerObserver {
  public:
   AndroidBatteryMetrics();
   ~AndroidBatteryMetrics() override;
 
-  // base::PowerObserver implementation:
-  void OnPowerStateChange(bool on_battery_power) override;
+  // Should be called by the embedder when the embedder app becomes visible or
+  // invisible.
+  void OnAppVisibilityChanged(bool visible);
 
  private:
-  // Called by base::android::ApplicationStatusListener.
-  void OnAppStateChanged(base::android::ApplicationState);
+  // base::PowerObserver implementation:
+  void OnPowerStateChange(bool on_battery_power) override;
 
   void UpdateMetricsEnabled();
   void CaptureAndReportMetrics();
   void UpdateAndReportRadio();
 
   // Whether or not we've seen at least two consecutive capacity drops while
-  // Chrome was the foreground app. Battery drain reported prior to this could
+  // the embedding app was visible. Battery drain reported prior to this could
   // be caused by a different app.
   bool IsMeasuringDrainExclusively() const;
 
   // Battery drain is captured and reported periodically in this interval while
-  // the device is on battery power and Chrome is the foreground activity.
+  // the device is on battery power and the app is visible.
   static constexpr base::TimeDelta kMetricsInterval =
       base::TimeDelta::FromSeconds(30);
 
-  std::unique_ptr<base::android::ApplicationStatusListener> app_state_listener_;
-  base::android::ApplicationState app_state_;
+  bool app_visible_;
   bool on_battery_power_;
   int last_remaining_capacity_uah_ = 0;
   int64_t last_tx_bytes_ = -1;
@@ -47,8 +50,7 @@ class AndroidBatteryMetrics : public base::PowerObserver {
   base::RepeatingTimer metrics_timer_;
   int skipped_timers_ = 0;
 
-  // Number of consecutive charge drops seen while the app has been in the
-  // foreground.
+  // Number of consecutive charge drops seen while the app has been visible.
   int observed_capacity_drops_ = 0;
 
   SEQUENCE_CHECKER(sequence_checker_);
@@ -56,4 +58,6 @@ class AndroidBatteryMetrics : public base::PowerObserver {
   DISALLOW_COPY_AND_ASSIGN(AndroidBatteryMetrics);
 };
 
-#endif  // CHROME_BROWSER_ANDROID_BATTERY_ANDROID_BATTERY_METRICS_H_
+}  // namespace power_metrics
+
+#endif  // COMPONENTS_POWER_METRICS_ANDROID_BATTERY_METRICS_H_