SystemMonitor refactoring: move power state monitor into a separate class called PowerMonitor

base/system_monitor/system_monitor_android.cc

-// Copyright (c) 2011 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.
-
-#include "base/system_monitor/system_monitor.h"
-#include "jni/SystemMonitor_jni.h"
-
-namespace base {
-
-namespace android {
-
-// Native implementation of SystemMonitor.java.
-void OnBatteryChargingChanged(JNIEnv* env,
-                              jclass clazz) {
-  SystemMonitor::Get()->ProcessPowerMessage(SystemMonitor::POWER_STATE_EVENT);
-}
-
-}  // namespace android
-
-bool SystemMonitor::IsBatteryPower() {
-  JNIEnv* env = base::android::AttachCurrentThread();
-  return base::android::Java_SystemMonitor_isBatteryPower(env);
-}
-
-bool RegisterSystemMonitor(JNIEnv* env) {
-  return base::android::RegisterNativesImpl(env);
-}
-
-}  // namespace base